UN chief Antonio Guterres announced Thursday a series of breakthroughs in talks with rivals in the Yemen conflict, including a ceasefire for a vital port.

The conflict has triggered what the UN calls the world's worst humanitarian crisis, with 14 million Yemenis now at the brink of mass starvation. 

Guterres, who flew in to Sweden late Wednesday, announced that the Yemeni government and Huthi rebels had agreed on  a ceasefire in the port of Hodeida, the main entry point for imported food and aid. 

He said the United Nations would play a "leading role" at the Red Sea port, which is currently controlled by the rebels.

In addition, the rivals have reached a "mutual understanding" on Yemen's third city of Taiz, the scene of some of the most intense battles in the conflict.

He said a new round of talks would take place at the end of January.

International pressure has been mounting to halt the fighting between the Iran-linked Huthis and the government of Abedrabbo Mansour Hadi, backed by Saudi Arabia and its military allies, with the US Senate, Saudi Arabia and the UAE honing in on the fragile talks. 

The warring parties have been in the rural Swedish village of Rimbo for a week to try to hammer out agreement on a number of key issues.

A source inside the talks had said earlier that mediators remained "positive" although there was "disagreement on the points of the proposals". 

The rebels control both the Red Sea port of Hodeida and the capital Sanaa. The Saudi led-military coalition controls Yemen's maritime borders and airspace. 

Guterres did not immediately refer to any deal on Sanaa airport, which has been closed to commercial flights for nearly three years.