Fighting between the pro-government Yemeni forces and the Houthi rebels in Yemen's Red Sea port city of Hodeidah intensified on Friday.

A local military official said on condition of anonymity that "non-stop battles are still taking place near Durayhmi district and other areas in the southern part of Hodeidah."

He said that scores of the Houthi rebels carried out a large-scale military operation in an attempt to capture Durayhmi's areas.

"The joint pro-government forces successfully foiled the Houthis' attack and engaged in intense fighting in the area," he added.

Another military source said that "the two warring sides are mobilizing their fighters for participation in the ongoing battles for the eighth consecutive day."

"The pro-government Giants Brigades mobilized several units of their soldiers to confront the Houthis' attacks in Hodeidah during the past two days," he said anonymously.

"The Houthis also dispatched scores of their fighters to prevent the on-ground military progress of the government forces," the source added.

On Thursday, UN Special Envoy for Yemen Martin Griffiths called on Yemeni parties to stop fighting in the port city of Hodeidah and respect a cease-fire agreement.

"This military escalation not only constitutes a violation of the Hodeidah cease-fire agreement but runs against the spirit of the ongoing UN-facilitated negotiations that aim to achieve a nationwide cease-fire, humanitarian and economic measures and the resumption of the political process," Griffiths said in a statement.

"I call on them to immediately stop the fighting, respect the commitments they made under the Stockholm agreement, and engage with the UN Mission to support the Hodeidah Agreement's joint implementation mechanisms," he added.

The port city Hodeidah, a vital lifeline for millions facing starvation, has seen a shaky cease-fire between the government and the Houthi rebels since they reached a UN-sponsored truce in Stockholm in December 2018.

The truce was seen as the first phase toward a nationwide cease-fire to end Yemen's more than five years of civil war.

Hodeidah is under the control of the Houthis, while the government forces have advanced to the southern and eastern districts.

Both sides have been blaming each other for truce breaches and military escalation.

Yemen has been mired in civil war since late 2014, when the Houthi militia seized control of several northern provinces and forced the internationally-recognized government of President Abd-Rabbu Mansour Hadi out of the capital Sanaa.