SANAA, April 7 (Xinhua) -- The UN Special Envoy Martin Griffiths arrived in Yemen's capital Sanaa on Sunday for crisis talks with Shiite Houthi rebel group.

Griffiths is set to offer a new plan for implementing the first phase of Stockholm Agreement in Hodeidah port city, a source close to the rebel group told Xinhua on condition of anonymity.

The plan detailed the operational steps of military redeployment and withdrawal of the rebels from the port city, the source said without elaborating further.

Griffiths has been shuttling between the rebels in Sanaa and the Yemeni government in the Saudi capital Riyadh to push the deal toward implementation.

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

Yemeni warring parties reached a peace deal in December last year in Stockholm as a first step toward a comprehensive political solution. However, the deal has hit a deadlock as the warring forces have largely held the cease-fire deal but failed to withdraw from the city.

Hodeidah is the key lifeline entry point for the country's most food imports and humanitarian aid.

Grinding into fifth year, the war has so far killed more than 10,000, displaced three million and pushed more than 20 million Yemenis into the brink of famine, according to the UN aid agencies.