SANAA, Yemen (AP) — Yemeni security officials say U.N. envoy Martin Griffiths has arrived in the capital, Sanaa, to discuss the "complex situation" in and around the key port city of Hodeida.

The Houthi rebels say their leader, Abdul-Malek al-Houthi, met with Griffiths on Sunday to discuss the implementation of peace deals from December talks with Yemen's internationally recognized government.

Yemen's warring sides agreed to a cease-fire in December, as well as a prisoner exchange that has yet to take place.

The conflict in Yemen began with the 2014 takeover of Sanaa by the Iran-aligned rebels. A Saudi-led coalition allied with the internationally recognized government has been fighting the Houthis since 2015.

The officials spoke anonymously as they weren't authorized to brief journalists.