UN envoy to Yemen Martin Griffiths (4th L) talks to Yemen's President Abdu-Rabbu Mansour Hadi (C) in Aden, Yemen, on July 10, 2018. The United Nations special envoy for Yemen arrived Tuesday in the southern port city of Aden to discuss ongoing peace efforts with President Abdu-Rabbu Mansour Hadi. (Xinhua/Ismail Rabidhy)

The United Nations special envoy for Yemen arrived Tuesday in the southern port city of Aden to discuss ongoing peace efforts with President Abdu-Rabbu Mansour Hadi.

In his second trip to Aden, Martin Griffiths will meet with President Hadi and his government officials in an attempt to prevent an all-out assault on the crucial port city of Hodeidah.

A government official told Xinhua that the Griffiths will brief Hadi "on his latest peace efforts and the results of his meetings with Houthi leaders in Sanaa."

The UN envoy is exerting hard efforts to avoid military escalation in Hodeidah, trying to bring Yemeni rivals back to the negotiation table instead of military confrontation.

Last month, Yemen's internationally-backed President Hadi received the UN envoy in Aden and insisted on full withdrawal of the Houthi rebels from the strategic port city of Hodeidah as a condition of a UN-brokered peace deal.

On July 4, Griffiths left the rebel-held capital Sanaa after his meeting with Houthi leader Abdul-Malik al-Houthi. Griffiths said the discussion was "fruitful."

On June 13, the Saudi-led Arab coalition, backing internationally-recognized government of Hadi, declared a major assault to recapture Hodeidah and the Yemeni western Red Sea coast from Houthis.

The Yemeni government and Saudi Arabia have repeatedly accused Houthis of using the port to smuggle in Iranian weapons. Both Houthis and Iran have denied the accusation.

Humanitarian agencies have warned of any attack on the port, saying it would lead to the world's biggest humanitarian catastrophe in modern history.

Hodeidah is the single most important point of entry for food and basic supplies to Yemen's northern provinces controlled by Houthis, including the capital Sanaa.

More than 121,000 residents have fled the war-torn city of Hodeidah and other parts of the province since June 1, the UN said this week.

The coalition intervened in Yemen's conflict in March 2015 to roll back Iran-allied Shiite Houthi rebels and reinstate Hadi.