At least 20 fighters of the Shia Houthi group were killed on Tuesday when they launched armed attacks on government-controlled areas and a strategic airbase in Yemen’s southern province of Lahj, a military official said.

He said the attacks were unleashed in the early hours of Tuesday by scores of Houthi fighters and their allies, with the aim to advance towards the government troops based inside the country’s biggest airbase in Lahj province, Xinhua reported.

According to the military source, the Houthi fighters captured a mountain overlooking the strategic military airbase of Al-Anad which is located about 60 km away from Yemen’s temporary capital of Aden.

The Yemeni military source said the pro-government army troops responded with heavy shelling, triggering intense battles that left about 20 Houthi fighters dead.

An army commander in Lahj said the Houthi militants attempted to infiltrate into areas surrounding the military airbase at dawn on Tuesday, but the pro-government army repelled the attacks, after carrying out Saudi-led airstrikes against them.

Pro-government troops backed by armoured vehicles of the Saudi-led coalition arrived in the area and engaged in more gunbattles with Houthis, leaving 10 soldiers injured, the commander said.

Witnesses said warplanes of the Saudi-led coalition launched heavy air raids and struck several plateaus seized by Houthi fighters outside Lahj province in an attempt to impede them from making more ground advances.

Tuesday’s fighting occurred despite the cease-fire that came into force on April 10 and was supposed to pave the way for the Kuwait peace talks, but both warring sides have complained of violations by each other, along with continuing heavy shelling and airstrikes.

The UN-brokered negotiations began in Kuwait on April 21 under the auspices of the United Nations to seek a reconciliation end to more than a year of civil war in Yemen.

The talks is the third of its kind since the conflict began after Houthi militias stormed the capital Sanaa and expelled the government into exile in September 2014. Previous peace negotiations had failed to end hostilities.

More than 60 days passed of ongoing consultations in Kuwait, but rival negotiators have so far failed to agree on the agenda in line with the UN Security Council Resolution 2216.

The resolution orders Houthi militias to withdraw from Sanaa and all other cities, hand back weapons and release political prisoners before forming new sharing transitional government.

Houthi and Saleh delegates have been insisting on forming a new transitional government before discussing other topics.

Both rival delegations keep trading accusations of cease-fire breaches all over the three weeks of talks that progress slowly.

The civil war has drawn in Saudi-led coalition on March 2015, in response to President Hadi’s call to restore his internationally recognised government to the capital, Sanaa.

The civil war has killed more than 6,000 people, half of them civilians, injured more 35,000 others, and displaced over two millions, according to humanitarian aid agencies.

Yemen’s conflict began after 2011 massive popular protests that demanded an end to the 33-year rule of then President Ali Abdullah Saleh.