At least two soldiers of Yemen's government forces were killed Monday in artillery shelling carried out by Houthi rebels in the country's southern province of Lahj, a military official said.

The heavy Houthi artillery attack targeted government-controlled sites and residential areas near the Hadd Yafea front in Lahj, the local official said on condition of anonymity, claiming that the shelling was indiscriminate.

Five soldiers were also injured in the attack, according to a local source. The government forces stationed at the front responded to the Houthi fire.

The incident marks an escalation of violence in the country's southern regions as the Houthis stepped up attacks against government forces and civilian areas during the past few days.

On Saturday, the Yemeni government forces raised their combat readiness in response to a large military parade held by the Houthis in the country's central province of Ibb.

During the parade, Mahdi Al-Mashat, head of the Houthis' Supreme Political Council, vowed to continue fighting for "freedom, independence, and full sovereignty" for Yemen. He also promised to introduce advanced weapons in the "next battle."

The Yemeni government's decision to raise combat readiness reflects growing concerns over the possibility of renewed conflict with the Houthis.

Yemen's civil war flared in late 2014 when the Houthi group seized control over much of the country's north and forced the internationally recognized government out of the capital Sanaa.