The arrest comes amid tensions over disputed elections in Venezuela, where the United States seized President Maduro's plane this week.
Venezuelan authorities have detained a U.S. Navy sailor traveling in the Latin American country, according to Pentagon officials.
White House national security spokesman John Kirby confirmed Wednesday that “one U.S. service member” had been detained and said Washington was seeking more information from Venezuelan authorities.
“We are obviously in contact, as appropriate, with Venezuelan authorities to try to obtain more information,” Kirby said. He added that “it was my understanding that this individual was on some type of personal trip and not on official government business.”
Two defense officials also told Reuters news agency that the sailor had traveled to Venezuela on personal leave and had not obtained the required authorization. The officials spoke on condition of anonymity and declined to provide further details.
A US State Department spokesman also said he was closely monitoring the situation.
The arrest comes as tensions rise over Venezuela's disputed election, with several countries, including the United States, rejecting President Nicolas Maduro's claims of victory.
Several countries, including the United States and Argentina, have gone so far as to recognize Maduro's opponent, Edmundo González, as the winner of the July presidential election.
On Monday, U.S. authorities seized a plane allegedly purchased for Maduro’s personal use, alleging a violation of sanctions imposed by Washington. Maduro’s government called the seizure “piracy.”
Hours later, Venezuelan authorities issued an arrest warrant for Gonzalez, charging him with conspiracy and other crimes. The United States joined several other countries in the Americas in condemning the move.
Several active-duty US military personnel have been detained while overseas in recent years.
Earlier this year, US Army Private Gordon Black, 34, was arrested after travelling to Russia to visit his girlfriend. Russian authorities sentenced Black in June to three years and nine months in prison after his girlfriend accused him of stealing from her. He remains an active member of the military but has been placed on unpaid leave.
Last year, Army Private Travis King fled to North Korea during a civilian mission along the Military Demarcation Line on the border with South Korea. King, who was already facing military disciplinary action, was detained by North Korean authorities and later released in the United States.
His lawyer said last week he would plead guilty to five charges, including desertion.
The United States has also recently exchanged prisoners with Venezuela.
In December, U.S. authorities freed a close Maduro ally, Alex Saab, in exchange for the release of 10 jailed U.S. citizens as well as a fugitive defense contractor at the center of a massive Pentagon bribery scandal.
