At least six people were killed in shelling carried out by the Houthi militia against a residential village in the country's southern province of Lahj late on Friday, a military source said.

"The anti-armor missiles indiscriminately landed on a government-controlled residential village in Lahj, killing six people including children and injuring 13 others," the local official said on condition of anonymity.

The official said that sporadic fighting broke out between the Yemeni government forces and the Houthis in areas near the province after the shelling.

"During the last 48 hours, the Houthis intensified their attacks and repeatedly attempt to advance militarily to capture new southern areas from the government forces," he added.

The recent military escalation came after the government and the Houthi group failed to extend a national truce that expired on Oct. 2, raising concerns about the return of violent conflicts to the war-ravaged Arab country.

The Saudi-backed Yemeni government said earlier this month that it started to tighten up security measures around key production facilities and ports in some southern regions as a precaution against Houthi attacks.

Yemen has been mired in a civil war since late 2014 when the Iran-backed Houthi militia stormed several northern cities and forced the Saudi-backed Yemeni government out of the capital Sanaa.

The war has killed tens of thousands of people, displaced 4 million, and pushed the country to the brink of starvation.