TEHRAN/Aden - Iran has called for all sides in Yemen's war to join UN-sponsored peace talks and accused Saudi Arabia of worsening the conflict with its military intervention against Tehran-backed rebels.

In talks with visiting UN envoy Ismail Ould Cheikh Ahmed on Wednesday, Iranian officials including Foreign Minister Mohammad Javad Zarif backed his efforts to resolve the conflict.

Stressing the UN role "in finding a political solution in Yemen," Zarif called for "the participation of all Yemeni groups" in talks Cheikh Ahmed is hoping to convene in Geneva this month, the IRNA news agency reported. UN efforts have repeatedly failed to resolve the conflict in Yemen, where the pro-Iran Shiite Huthi rebels have seized control of large parts of the country, including the capital Sanaa.

A Saudi-led coalition launched air strikes against the rebels in March and has sent ground troops in support of a fightback by forces loyal to President Abedrabbo Mansour Hadi.

In separate talks with Cheikh Ahmed, Iran's deputy foreign minister told the envoy Saudi Arabia's intervention was making security worse. "For the Islamic Republic of Iran, the security of Yemen, Saudi Arabia and the region are important," the ISNA news agency quoted Hossein Amir Abdollahian as saying.

"But Saudi Arabia cannot endanger the security of others to provide its own security," he said. Cheikh Ahmed for his part praised Iran as "an important and influential country in the region" which has "a determining role in the fight against terrorism," IRNA reported. The humanitarian crisis in Yemen has been identified by the United Nations as one of the world's worst, with 80 percent of the country's population on the brink of famine. Moreover, Yemeni pro-government forces advancing into the strategic province of Taez were battling rebels on the outskirts of its second largest town on Thursday, military sources said.

Eight rebels and two loyalists were killed in the fighting for Rahida, the pro-government sources said. The town lies on the main road from government-held territory towards Taez, Yemen's third largest city, 40 kilometres (25 miles) further north, where loyalist troops have been besieged by the rebels for months.

Loyalist forces were backed by significant reinforcements from a Saudi-led coalition which intervened in support of President Abedrabbo Mansour Hadi in March.

Hadi returned from Saudi exile on Tuesday as the offensive against the Huthi Shiite rebels and their allies got under way.

The coalition carried out at least 10 air strikes against rebel positions in and around Rahida during the night, the military sources said.

Breaking the siege of Taez is seen as crucial for the recapture of other central provinces and opening the way to the rebel-held capital Sanaa further north. It is also important for securing the south, where loyalists have retaken five provinces from the rebels since July, including second city Aden, where Hadi has set up base. In their advance out of the south, pro-government forces have also been battling the rebels in Marib province east of the capital. Hundreds of reinforcements were deployed to the province on Thursday, equipped with dozens of military vehicles newly arrived from neighbouring Saudi Arabia, military sources said.

Loyalists control Marib city, 140 kilometres (90 miles) from Sanaa, but they have so far failed to secure the rest of the province, which is the source of much of Yemen's oil output. The latest reinforcements came as Saudi Arabia's regional rival Iran called on all sides in the conflict to join UN-sponsored peace talks in Geneva later this month. Tehran accused Riyadh of deepening the conflict with its military intervention against the rebels. According to United Nations, more than 5,700 people have been killed since the intervention began in March, nearly half of them civilians.