Yemen's Houthi rebels intensified their attacks against areas controlled by the pro-government forces in the country's southern part on Tuesday evening, a military official said.

The military source said on condition of anonymity that "Houthi fighters launched a series of attacks against different locations in areas controlled by the pro-government forces in the southern province of Dhale."

The Houthi attacks targeted the pro-government military locations on northern outskirts of Dhale near Qataba district, the source said.

"The pro-government forces are trying to repulse the Houthi attacks that were ferocious and caused casualties among the soldiers positioned there," he added.

Many families were forced to leave their houses in the areas located around Qataba district as both sides began exchanging heavy artillery shelling.

In April, the Iranian-allied Houthi fighters launched a series of intense armed attacks on the positions of Yemeni government forces and succeeded in seizing the district of Al Husha in the west of Dhale.

The areas in the north and west of Dhale, 138 km north of Aden, have been witnessing non-stop fightings between government forces and Houthi fighters for about four years.

Yemen has been plagued by a civil war since late 2014 after Houthi rebels forced the internationally-recognized government of President Abd-Rabbu Mansour Hadi into exile.