Amid heavy security, a tentative return of street life in Caracas.

The United States on Wednesday seized an oil tanker in the North Atlantic that had evaded its effort to crack down on Venezuela’s energy exports, U.S. officials said, capping a pursuit that had lasted more than two weeks and raised tensions with Russia.Around the same time, U.S. forces boarded another oil tanker in international waters near the Caribbean, a sign that President Trump planned to continue to enforce a partial blockade on Venezuelan oil as he pressured the country’s new leader.The first tanker, formerly known as the Bella 1 and recently re-registered with Russia as the Marinera, had eluded the U.S. Coast Guard after being stopped in the Caribbean on its way to pick up oil in Venezuela. Its crew began flying a Russian flag in a last-ditch effort to avoid seizure while Russia dispatched at least one naval vessel to meet and escort the ship. Russia made a formal diplomatic request last week asking the United States to stop its pursuit.But there were no Russian vessels in the area when the Coast Guard boarded the ship on Wednesday morning, averting the possibility of an armed standoff between the two countries, according to two U.S. officials briefed on the operation who spoke on the condition of anonymity to discuss a sensitive matter. The crew of the tanker did not resist the boarding attempt, one of the U.S. officials said. The vessel was not carrying oil when it was boarded.Still, the military dispatched a large force to assist the Coast Guard, including a Navy P-8 submarine-hunting aircraft and AC-130 gunships. Several U.S. military aircraft left bases in Britain on Wednesday morning heading toward the tanker, according to flight-tracking sites. The ship had been sailing northeast in the Atlantic in Iceland’s exclusive economic zone and near that of Britain, according to ship-tracking data from MarineTraffic.Kristi Noem, the homeland security secretary, said in a statement on Wednesday that the Marinera had made “a desperate and failed attempt to escape justice.” She commended the Coast Guard for pursuing it “across the high seas and through treacherous storms.”At a news briefing on Wednesday, Karoline Leavitt, the White House press secretary, said that members of the Marinera crew — which had sailed the vessel away from the Coast Guard’s first boarding attempt last month — could face legal action.“They will be brought to the United States for such prosecution, if necessary,” Ms. Leavitt said.The seizing of the tanker signals that the United States intends to maintain its partial blockade on Venezuelan oil after capturing the country’s leader, Nicolás Maduro, on Saturday in a stunning military operation in Caracas. Revenue from oil sales powers Venezuela’s economy, and squeezing it would put pressure on Mr. Maduro’s successor, Delcy Rodríguez.Mr. Trump has claimed that Venezuela will hand over tens of millions of barrels of oil to the United States. Energy Secretary Chris Wright said on Wednesday that the United States intended to oversee the sale of Venezuela’s oil production “indefinitely.”In another sign of continuing pressure, the Coast Guard on Wednesday intercepted a second oil tanker. The ship, called the M Sophia, was not flying a valid national flag, making it liable to be boarded, according to a U.S. official. The International Maritime Organization said the ship’s flag state was unknown.Ms. Noem posted a video on social media showing the boarding of the ship, which The New York Times verified was the M Sophia. The footage showed a helicopter hovering near the tanker’s deck as armed men descended and moved toward the bridge.According to TankerTrackers.com and Kpler, two companies that track global oil shipments, the M Sophia was loaded with about 1.8 million to 2 million barrels of Venezuelan crude.The tanker has carried Venezuelan oil for years, often sailing under the false identity Varada Blessing, the name of a decommissioned vessel, when picking up those cargoes before transporting them to China, according to TankerTrackers.com. The ship has also carried Russian and Iranian oil to China, according to Kpler.The M Sophia has spoofed its transponder signals to conceal its movements, making it appear in tracking data as though it were off the coast of West Africa while it was operating near Venezuela. The New York Times confirmed the tanker’s real location using satellite imagery and photographs provided by TankerTrackers.com.ImageThe oil tanker M Sophia off the coast of Venezuela this year. The name painted on the hull, Varada Blessing, is a false identity borrowed from a decommissioned vessel as part of efforts to conceal its true identity.Credit...TankerTrackers.comThe vessel was part of a group of at least 16 tankers identified by The New York Times that departed Venezuela this week in defiance of the U.S. naval blockade. The M Sophia is the first known ship from that group that the United States stopped.The U.S. Southern Command said in a statement that the Coast Guard would escort the ship to the United States for “final disposition.” The Treasury Department had placed the ship under sanctions last January for its previous involvement in the Russian oil trade. But the U.S. authorities did not have a warrant to take possession of the vessel, according to an American official.That was in contrast to the Marinera, which a federal magistrate judge had issued a seizure warrant for last month, based on the vessel’s history of transporting Iranian oil for groups linked to terrorism.Both ships are part of a so-called shadow fleet that has transported oil for Russia, Iran or Venezuela in violation of sanctions imposed by the United States and other countries, according to Kpler and TankerTrackers.com. The United States has cracked down on them since Mr. Trump last month ordered a “complete blockade” on oil tankers under sanctions going to and from Venezuela.“The blockade of sanctioned and illicit Venezuelan oil remains in FULL EFFECT — anywhere in the world,” Defense Secretary Pete Hegseth posted on social media after the seizure of the Marinera.Britain said on Wednesday that it had helped the United States to board the Marinera by providing air surveillance and a naval support vessel, as well as bases to U.S. military assets. “This ship, with a nefarious history, is part of a Russian-Iranian axis of sanctions evasion which is fueling terrorism, conflict and misery from the Middle East to Ukraine,” said John Healey, the British defense secretary.Russia’s Ministry of Transport said in a statement on Wednesday that it had lost contact with the Marinera, and that U.S. forces had boarded it outside the territorial waters of any state.The Russian ministry said that the ship had received a temporary registration in the national ship registry on Dec. 24, adding that in accordance with the 1982 U.N. Convention on the Law of the Sea, “no state has the right to use force against vessels duly registered in the jurisdictions of other states.” The United States has not ratified the convention but generally recognizes its provisions as customary law.At least four other oil tankers that operated in Venezuelan waters in recent weeks have similarly switched to Russian flags, according to an official Russian vessel registry. The U.S. crackdown has led some in the country to call for more action.“An attack on a Russian-registered ship is an attack on the Russian territory, from the legal perspective,” said Oleg Tsaryov, a pro-Russia Ukrainian politician who lives in Moscow and said he knew the owner of the Marinera. “It’s a real shame that the Russian forces have not reacted.”The Marinera has a crew of Russian and Ukrainian sailors, Mr. Tsaryov said in an interview.The seizure of the ship, which came on a Russian holiday, was met with a muted response from Moscow. The Foreign Ministry issued a statement calling on the United States to “ensure humane and dignified treatment” of Russians aboard the vessel and to respect their rights and interests. The Kremlin did not comment on the episode.The tepid response comes as Russia invests in improving relations with Mr. Trump, who has been leading an effort to broker an end to the war in Ukraine. Still, some Russian lawmakers criticized the United States for the seizing.Andrei Klishas, a member of Parliament, accused Washington of engaging in “outright piracy on the high seas” for carrying out a “law enforcement operation” that resulted in the killings of several dozen people in Venezuela.Aleksei Zhuravlev, the deputy chairman of the defense committee in Russia’s lower house of Parliament, said the seizure of a Russian-flagged ship “could be classified as an illegal crossing of our border, in other words, a full-fledged military invasion of Russia.”A U.S. official said that federal agents from Homeland Security Investigations, the department’s law enforcement arm, were planning to board the vessel and interview the crew.Reporting was contributed by Riley Mellen, Paul Sonne, Milana Mazaeva, Stephen Castle, Anatoly Kurmanaev, Shawn McCreesh and Tyler Pager.Note: The International Maritime Organization issues an IMO number, a permanent identification number, that remains associated with a vessel throughout its lifetime unlike a ship’s name, which can change frequently. The ships in this article are Marinera (9230880, previously known as Bella 1) and M Sophia (9289477).