UNITED NATIONS: UN Secretary-General Antonio Guterres on Thursday called on Yemen's warring sides to engage in UN-brokered talks without imposing pre-conditions after the government and rebels put forward demands.

Yemen's government and Huthi rebels began talks in Sweden on Thursday aimed at ending nearly four years of war that have pushed the impoverished Arab country to the brink of mass starvation.

Guterres "urges the parties to make progress on the agenda for the consultations ... by exercising flexibility and engaging in good faith and without pre-conditions," said a UN statement.

The UN chief appealed to the sides to continue the de-escalation of Hodeida, the rebel-held port city that is a key entry point for humanitarian aid and vital supplies.

In Sweden earlier, Yemen's foreign minister called for the withdrawal of the Huthis from Hodeida, a demand rejected by the rebels.

The United Nations is offering to play a supervising role in Hodeida, but the Saudi-led coalition backing Yemen's government is insisting on a rebel withdrawal as a first step.

The coalition, which includes troops trained by the US and UAE, has for months led an offensive to retake Hodeida, the last rebel stronghold on Yemen's Red Sea coast and the conduit for 90 percent of vital food imports.