Sanaa, Nov 22, 2018 (AFP)

The United Nations envoy will visit Yemen's embattled city of Hodeida this week, a UN source said Thursday, ahead of peace talks set for December in Sweden.

Martin Griffiths, who arrived in the rebel-held capital Sanaa on Wednesday, was in the country to lay the groundwork for the upcoming negotiations aimed at ending almost four years of devastating conflict.

The British diplomat is expected to visit the lifeline port city of Hodeida on Friday, a UN source told AFP.

The purpose of Griffiths's visit was to encourage the Iran-aligned Huthi rebels and government forces backed by a Saudi-led coalition to remain calm ahead of the talks in Stockholm, the source said.

Both sides have in the past week expressed support for the envoy and his mission to hold discussions, but military officials have said intermittent clashes continued to erupt in the Red Sea city of Hodeida.

Mohammed Ali al-Huthi, head of the Huthi rebels' Higher Revolutionary Committee and an influential political figure, tweeted Thursday that he "hopes there is no escalation in military operations by the coalition following Griffiths's visit to Hodeida".

UN agencies say up to 14 million Yemenis are at risk of starvation if fighting closes the port of Hodeida, from which nearly all imports and humanitarian aid pass.