ADEN, Yemen, April 1 (Xinhua) -- Warplanes of the Saudi Arabia-led coalition launched intensified airstrikes against Houthi-held sites in Yemen's southern province of al-Dhalea on Monday, a government official told Xinhua.

The Saudi-led airstrikes came as a support for the government forces that are engaging in ongoing armed confrontations with the Houthi rebels in the northern parts of al-Dhalea, the official said on condition of anonymity.

The airstrikes resulted in killing and injuring dozens of Houthi fighters in addition to destroying a number of armored vehicles belonging to the Houthi group, the official said.

Other local sources said that more than 18 government soldiers were killed during the ongoing armed confrontations with the Houthi rebels within the last 24 hours in al-Dhalea's northern entrances.

The fighting heavily intensified after the arrival of large reinforcements from the pro-government southern resistance forces to the frontlines in al-Dhalea during the past few hours.

High-ranking military leaders from the government forces and the southern resistance (a well-trained force of the pro-secession Southern Transitional Council) visited the battlefields with the Houthis in al-Dhalea.

Last Thursday, the Houthis launched a series of intensive attacks on positions of the government forces in the northern part of al-Dhalea and managed to control key mountainous hills overlooking government-controlled areas in the province.

The areas located in the north and west of al-Dhalea have been witnessing continuous fighting between government forces and Houthi fighters for nearly four years.

Yemen has been plagued by a civil war since late 2014 after Houthi rebels revolted against the Saudi-backed internationally recognized government of President Abd-Rabbu Mansour Hadi.

The rebels advanced from their far northern stronghold of Saada province toward the south, seizing control over much of the country's north, including the capital Sanaa, which triggered the deadliest war.