Fighting between Yemen's government troops and Houthi rebels in the northeastern province of Jawf on Sunday left at least 20 fighters from both sides dead, a local government official said.

The clashes in al-Aqabah area in the southwestern edge of the government-held Jawf province wounded dozens of others and forced dozens of families to flee, the official in Jawf told Xinhua by phone on condition of anonymity.

He said the clashes expand to areas near the ancient town of Baraqish, also in Jawf, some 140 km northeast of the capital Sanaa.

Meanwhile, the Saudi-led coalition backing the Yemeni government forces continued its airstrikes on Houthi positions in the area, with the Houthi-run al-Masirah TV on Sunday reported at least 21 coalition airstrikes.

Fierce clashes and airstrikes also escalated Sunday on several fronts in Nehm district of the rebel-held Sanaa, as the Houthi rebels seized control of mountains overlooking the roads linking Sanaa with Jawf and Marib province, according to pro-government news website al-Masdar Online.

The fighting in Nehm and Jawf escalated after last week's Houthi missile attack in the adjacent Marib province killed more than 100 Yemeni government troops.

The UN envoy to Yemen Martin Griffiths has called on all Yemeni parties "to cease all military activities," warning that such escalation could fail the fragile peace process.

Yemen has been mired in a civil war since late 2014, when the Iran-backed Houthi rebels seized control of much of the country's north and forced the Saudi-backed government of President Abd-Rabbu Mansour Hadi out of Sanaa.