Aden (AFP) – Yemeni government forces have advanced into the Red Sea town of Mokha but Shiite Huthi rebels are still putting up fierce resistance, a military official said on Saturday.

Forces loyal to President Abedrabbo Mansour Hadi, backed by a Saudi-led Arab coalition, captured the police headquarters and several surrounding streets late on Friday, the official said.

Deadly clashes have shaken the town after loyalist forces launched an offensive nearly three weeks ago to oust the rebels and their allies from the southern part of the Red Sea coastline.

Since Friday alone, at least 19 rebels have been killed and 23 wounded, a medical source in the rebel-held port city of Hodeida further north said.

Eight loyalist troops have been killed and 13 wounded, medical sources in the government-held second city of Aden said.

The rebels’ only escape route is to the north after loyalist forces surrounded Mokha from the east and the south, the military official said.

The waters off the port are blockaded by coalition warships and Apache helicopters.

Mokha was Yemen’s main port serving as its export hub for coffee until it was overtaken by Aden and Hodeida in the 19th century.

Nearly 260 combatants have been killed since government forces launched their drive up the Red Sea coastline on January 7.

They have already retaken the Dhubab district further south in their biggest advance in months.

The offensive comes with the president and his coalition backers under mounting international pressure to agree to a UN ceasefire plan.

In a speech to the Security Council on Thursday, UN envoy Ismail Ould Cheikh Ahmed criticised Hadi for rejecting his proposals for a transition that would see him cede much of his power to a vice president who would oversee a government of national unity.

“President Hadi continues to criticise the proposals without agreeing to discuss them and this will hinder and impede the path towards peace,” the envoy said.

The UN has also criticised the coalition air and sea blockade of rebel areas, warning that it is impeding the delivery of desperately needed aid to millions of civilians.

The world body says about 14 million people — nearly 80 percent of the Yemeni population — are in need of food aid.

Elsewhere, suspected Al-Qaeda gunmen Saturday killed the special security forces head in the southern province of Abyan, Major Rushdi al-Alwani, and three guards, a security official said.

He said gunmen ambushed Alwani’s car in the town of Loder.

Al-Qaeda’s franchise in Yemen, Al-Qaeda in the Arabian Peninsula (AQAP), is seen by Washington as the jihadist network’s most dangerous franchise.

It and the rival Islamic State group have exploited the power vacuum created by fighting between the government and Huthis to expand their presence in Yemen, especially in the south.