The UN Special Envoy to Yemen Martin Griffiths arrived on Monday in the Yemeni rebel-held capital Sanaa to break a stalemate in the Red Sea port city of Hodeidah, Houthi-controlled Saba news agency reported.

Griffiths' visit aimed to push forward implementing a cease-fire and withdrawal of Yemen's rival forces from the port city in line with a peace deal reached in Stockholm last month.

Under the truce, the withdrawal from the ports of Hodeidah, Salif and Ras Issa, and critical parts of the city associated with humanitarian facilities should be completed within two weeks after the cease-fire enters into force, while the full withdrawal should be completed within a maximum period of 21 days.

The cease-fire deal went into force on Dec. 18 last year but the withdrawal of the rival forces has yet to be fulfilled.

It was Griffiths' second trip to Sanaa this month after a previous one on Jan. 5 to push for the Hodeidah peace process.

The UN added that the discussions have been stalled because of different interpretations of the Stockholm Agreement over who would control key points of Hodeidah during a partial cease-fire.

Saudi Arabia is leading an Arab military coalition that intervened in Yemen in 2015 to support the government of President Abd-Rabbu Mansour Hadi after the Houthi rebels forced him into exile and seized much of the country's north, including the capital Sanaa and Hodeidah.

The four-year war has killed more than 10,000 people, mostly civilians, displaced 3 million others and pushed the country to the brink of famine.