WASHINGTON — A Marine veteran detained in Yemen for more than a year was released Sunday after diplomatic negotiations, the State Department announced.

The detainee, Wallead Yusuf Pitts Luqman, 37, was abducted in April 2015 as he tried to leave the country after having taught English there for two years. He was then held in secret by the Houthis, a Shiite rebel group.

Secretary of State John Kerry, who was involved in the negotiations to free Mr. Luqman and was in touch with his family, announced the news of his release in a statement.

Mr. Kerry also thanked the government of Oman for its assistance and said, “We also recognize this positive gesture by the Houthis.”