Saudi Arabia is boosting its efforts to defeat Iranian-backed Houthi insurgents in war-torn Yemen, sending in more heavy weaponry and troops in recent days.
One Yemeni military source told the French news agency that Riyadh has sent in dozens of tanks, armored vehicles and personnel carriers during the past 48 hours via Wadia, a border post in northern Yemen.
Several days ago, 2,800 Arab coalition troops landed in Yemen. Most were Saudi forces - special-operations, intelligence and logistics personnel - along troop units from the United Arab Emirates.
After joining forces with Yemeni troops loyal to deposed President Abdu Rabu Mansour Hadi, the combined Arab force recaptured the key Al-Anad military base and began advancing northward toward Sana'a, the Houthi-controlled Yemeni capital.
Hadi fled to exile in Riyadh months ago as ethnic Houthis and other rebels advanced on his last outpost, the southern port city of Aden. Government loyalists regained control of Aden last month.
A Saudi-led Arab coalition has been carrying out airstrikes since late March against rebel positions in Yemen, which was the Arab world's poorest country even before the violence this year.
With Yemeni government loyalists once again in control of southern Yemen, a passenger plane arrived in Aden's airport Thursday, the first civilian aircraft to land there in four months. The flight from Djibouti carried 158 Yemenis who had fled the fighting in their country.