N. Korea says it will send back S. Korean fishing boat

North Korea says it will send back a South Korean fishing boat and its crew who were detained for crossing the eastern sea border between the rivals.

North Korea's announcement Friday came hours before U.S. Secretary of Defense Jim Mattis visited the heavily-armed land border between the Koreas and stressed Washington's commitment to defend ally Seoul against North Korean threats.

Experts say it's unclear whether the North's gesture reflects intentions to improve relations with the South amid heightened animosity over Pyongyang's expanding nuclear program.

Seoul's Unification Ministry says North Korea last detained a South Korean fishing boat in 2010 before repatriating it. South Korea often sends back North Korean fishermen who enter its waters, but it's more unusual for better-equipped South Korean boats to drift into the North.