Months of fighting in Yemen are coming to a head with an offensive by pro-government forces to retake the strategic province of Taez and pave the way towards the rebel-held capital.
This week, government forces backed by a Saudi-led coalition, launched an all-out offensive to push the Iran-backed Shiite rebels out of the southwestern province, and to relieve loyalists besieged in its capital.
The fighting, which has killed dozens on both sides, risks worsening an already dire humanitarian situation for the 700,000 inhabitants of Taez city, the International Committee of the Red Cross (ICRC) told AFP.
Stretching to the strategic Bab el-Mandab strait at the mouth of the Red Sea, the province could be "the key for the liberation of other provinces, including Ibb and Baida" in central Yemen and opening the way to the north, including Sanaa, said analyst General Thabet Hussein Saleh.
Regaining Taez would be of "strategic importance to secure the southern provinces" and Aden, the country's second city, said Saleh, deputy director of the Yemen National Centre for Strategic Studies.
The emergence of hard-to-control armed groups, mostly claiming to be jihadists, is feeding a feeling of insecurity, mainly in Aden.
President Abedrabbo Mansour Hadi fled Sanaa in March after escaping from house arrest under the rebels, known as Huthis. He took refuge in the port city, which became the country's temporary capital.
Shortly thereafter, he fled to asylum in Riyadh, capital of neighbouring Saudi Arabia, after the insurgents seized Aden.
But loyalist forces and southern fighters, backed by coalition air and ground support, pushed the rebels out of Aden and four other southern provinces in the summer.
-Loyalists face 'difficulties' -
Hadi returned to Aden this week to supervise the operation in Taez, which General Saleh said "faces difficulties".
The rebels and their allies, forces loyal to ousted president Ali Abdullah Saleh, "control most of the province of Taez, while the (pro-Hadi) Popular Resistance is weak," General Saleh said.
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The province is "large, with the Huthis and their allies controlling most of it," while loyalists are holding most of the provincial capital against a Huthi siege, he said.
The Popular Resistance in Taez is "not as organised as it is in the south" said Saleh, adding that the city is "still divided, with some supporting the Huthis and Saleh."
"We are advancing on three fronts to break the siege of Taez" city, said General Fadhel Abbes, commander of the major Al-Anad air base.
He spoke of a "collapse among the ranks of the Huthis, with some surrendering".
Security expert Mustafa Alani, from the Geneva-based Gulf Research Centre, said: "the battle of Taez is crucial to defeat the Huthis and their allies".
The coalition has "delivered important reinforcements coming from Saudi Arabia, the United Arab Emirates and Qatar" to help pro-Hadi forces in "winning the battle."
"Recapturing the province of Taez will change the balance of power in the military and political fields. It will be the key to liberate other province and open the way to resume the process of political transition," said Alani.
A process aimed at drafting a new constitution and pave the way for elections fell apart after the Huthis advanced from their northern stronghold and occupied the capital in September 2014.
Meanwhile, civilians are being hit most in this conflict. According to UN figures, 2,695 civilians have been killed and 5,316 others wounded since March 26.
A total of 5,723 people have been killed between late March and the end of October.
The siege imposed on Taez is "preventing the entry of commercial goods and hindering the delivery of humanitarian assistance," lamented the Red Cross.
"The ICRC has been repeatedly requesting an authorisation from parties on the ground to deliver critical and life saving medical and surgical supplies to lead hospitals in Taez to no avail," it said.
The province is "currently the worst hit governorate across Yemen with an extremely dire humanitarian situation," it said.