DUBAI (AFP) - Clashes erupted on Tuesday morning (Dec 18) in Yemen just minutes after a ceasefire deal took effect in the country's flashpoint port city of Hodeida, a pro-government official said.

The official told AFP that sporadic clashes in the east of the Red Sea city - whose port serves as a crucial gateway for humanitarian aid - are ongoing despite a truce deal that was to be implemented at midnight local time.

The United Nations said on Monday that the deal was to be implemented at midnight, even though the agreement reached in Sweden was announced on Thursday between Yemen's Saudi-backed government and the Houthi rebels. The agreement had included an "immediate ceasefire" in Hodeida and its surroundings.

Shortly before the agreement was to take effect on Monday, Yemen's internationally-recognised government called on its forces to "cease fire in Hodeida province and Hodeida city", according to a copy of a statement received by AFP.

The Houthi rebels also said they would commit to the agreement.

Impoverished Yemen has been mired in fighting between the Houthi rebels and troops loyal to President Abedrabbo Mansour Hadi since 2014.

The war escalated in 2015 when a Saudi-led military coalition stepped in on the government's side.

The conflict has since killed nearly 10,000 people, according to the World Health Organisation. But some rights groups believe the toll to be far higher.