Yemeni military sources said on Sunday that the Iranian backed Houthi militias are pushing towards the port city of Aden in the southern part of the country and have recaptured positions they had lost in the recent months.
According to sources, the rebels are now positioned on a strategic hill in Lahj Province, which overlooks the Al And Airbase.
The base is currently housing Sudanese troops, who are part of the Saudi-led coalition, the coalition launched a military campaign in March, attacking the rebels and anti-government forces.
Saudi Arabia set up the coalition to restore the legitimacy of the Yemeni President Abd Rabbu Mansour Hadi and started to carry out air strikes against the Houthi militants in Yemen.
The Iranian backed Houthis are allied with the forces loyal to the former President Ali Abdullah Saleh and they have been fighting against the Saudi-led coalition for more than 7 months.
A military source told the AFP that the rebels deployment near the base raises concerns and it "poses a real danger to pro-government and coalition forces."
In July, forces loyal to the Yemeni President Abd Rabu Mansur Hadi, launched an offensive in which they pushed the Houthis out of the city of Aden and other four cities, Lahj, Daleh, Abyan, and Shabwa.
These clashes left 16 people dead, including nine loyalists, the sources said, adding that many others were wounded.
Yemeni ministers returned to the city of Aden in September, after six months of exile in Saudi Arabia. They had fled the country with Hadi after Houthis attacked Aden.
Houthis advance in the south, as the United Arab Emirates welcomes its first returning troops from Yemen. More than 68 Emirati soldiers were killed in Yemen during coalition operations.
In addition to the ongoing battles between the Houthi militants and the Saudi-led coalition, Al Qaeda and ISIS also control large swaths of territory in Yemen.
In the recent weeks, the Saudi-led coalition made advances in the east of Yemen's capital Sanaa and captured Bab al Mandeb, which connects the Red Sea with the Gulf of Aden. But Houthis have seized a military base following clashes with pro-government troops. Six loyalists and 11 Houthis were killed during to the clashes, a military source said.
According to the United Nations, around 5,400 people, including more than 2,100 civilians, have been killed in fighting and air strikes since the operations carried out by Saudi-led coalition started on March 26.