SANAA, Yemen (AP) — Hundreds of pro-government troops and dozens of tanks and armored personnel carriers pushed north toward the al-Anad military base in Yemen on Monday, as Saudi-led coalition airstrikes cleared the path for their advance, military officials said.

The officials said allied fighters have gained control of the western gate of the key base.

Houthi officials said the base remains under rebel control amid fierce fighting and continuous Saudi-led coalition airstrikes.

Al-Anad, once the site of U.S. intelligence operations against al-Qaida's powerful Yemeni affiliate, is the main rebel encampment in the country's south.

Saudi and Emirati troops are assisting Yemeni pro-government forces at al-Anad by operating many of the tanks and sophisticated military equipment, military officials said.

A Yemeni military official said thus far, few Yemeni troops have been trained in operating the tanks that have arrived by sea from Gulf allies in recent weeks. He added that the Yemeni military sought help from coalition countries in the al-Anad operation, calling them "partners in the liberation operation of Aden and other provinces."

Military officials said allied fighters have cut off the main road between al-Anad and Taiz, which has seen heavy fighting, for the first time since the Houthis took control of it in March.

Soldiers and allied pro-government forces are also reinforcing the front in the strategic southern city of Zanjibar, west of Aden, military officials said.

All officials spoke on condition of anonymity because they were not authorized to speak to reporters.

The fighting in Yemen pits the Houthis and troops loyal to former President Ali Abdullah Saleh against southern separatists, local and tribal militias, Sunni Islamic militants and loyalists of exiled President Abed Rabbo Mansour Hadi, who is now in Saudi Arabia.