Sporadic clashes erupted between the pro-government forces and the Houthi rebels in Yemen's Red Sea port city of Hodeidah on Sunday, a military official said.

"The Houthis launched a large-scale attack on several positions of the joint forces stationed in Tuhyata district in the south of Hodeidah, using heavy and medium weapons," the military source of the pro-government Giants Brigades said on condition of anonymity.

"The pro-government forces engaged in ferocious clashes with the Houthis, causing casualties among the attackers as well as the loss of their military equipment," he added.

The Houthis also fired heavy shells at the government's military sites in Hays area in the southeast of Hodeidah, the source noted.

A day earlier, the pro-government forces announced the abortion of a Houthi attack and killing seven of the attackers in Hodeidah's district of Tuhyata.

Last month, the United Nations started deploying cease-fire observers in Hodeidah, establishing five observation points near the military contact lines between the two warring parties.

The observation points are manned by liaison officers from both parties in accordance with a UN-sponsored cease-fire agreement reached in Stockholm in December 2018.

As the main Yemeni port city along the coast of the Red Sea, Hodeidah is the key lifeline entry of most Yemen's commercial imports and humanitarian aid.

The grinding war of more than four years has pushed over 20 million people to the verge of starvation.

The Iran-allied Houthi rebels control much of Hodeidah while the Saudi-backed government troops have advanced to its southeastern districts.

The cease-fire deal in Stockholm was seen as the first phase toward achieving a comprehensive political solution to the civil war.