Sporadic armed attacks erupted on Sunday between pro-government military forces and militants of the Houthi rebel group in Yemen's port city of Hodeidah, a security official said.

"Both sides exchanged heavy artillery shelling sporadically in areas located in the southeastern part of Hodeidah," the local security source said on condition of anonymity.

He said that "several Houthi fighters launched an attack against the sites of the joint pro-government forces in the Hays district."

But the joint pro-government forces confronted the Houthi attackers and foiled their military assault, the source said.

The Houthi attack came just one day after the pro-government forces announced "the killing of around 80 Houthi fighters while repelling their attacks against Hays, Tuhyata, and Durayhmi districts during the past days."

The Houthi authorities in Sanaa made no comments on the government's reports about the situation in Hodeidah.

Media outlets close to the Houthi group blamed the government forces for establishing new military sites and fortifications in Hays despite the ceasefire brokered by the United Nations.

In October, 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 the cease-fire agreement reached last year in Sweden which also called on both warring sides to move forces away from ports and parts of the strategic city.

However, sporadic exchange of gunfire and artillery shelling continued to rock the port city despite the presence of the cease-fire observers.

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 five 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.