Saudi Arabia said Friday its jets and ground forces blasted Yemen rebels on the two countries' rugged border after being attacked and briefly occupied by the Shiite insurgents.

Sporadic shelling could be heard from the border around the Jebel al-Dukhan mountain and jets screeched overhead after two days of aerial bombing of the Shiite rebels, according to an AFP journalist.

Saudi media reported several Saudi civilians had been killed by rebel shelling, while the rebels, forced close to the border by a Yemeni government military campaign, said they captured a number of Saudi soldiers.

- We will show images of them within hours - the rebels' spokesman Mohammed Abdulsalam told Al-Jazeera television by telephone.

- Our demands are clear: there is no justification at all for this Saudi outrageous aggression - he said.

The Saudi air force struck the border zone on Wednesday and Thursday from southern Jizan province to "neutralise the firing by intruders" and to clear areas where they had encroached on the kingdom's territory, the government said.

Earlier, a government adviser said Saudi F-15 and Tornado jets had bombed camps of the Zaidi rebels inside Yemeni territory.

- We took back a small piece of territory and hit their camps around Saada - the rebel stronghold province over the border.

- They've been hit hard and it's ongoing - the adviser told AFP, adding the move was taken with the knowledge of the Yemeni government.

It was the first acknowledged Saudi involvement in the Yemen government's three-month campaign against the rebels, also known as the Huthis, in the country's mountainous northwest corner.

The Saudis said they were responding to an incursion on Tuesday, when the rebels attacked a border post killing one Saudi border patrol and injuring 11 others.

The rebels also occupied two small villages before being driven out, the government said.

But the government statement maintained Saudi forces attacked rebel positions "inside Saudi territory" around the 2,000-metre (6,600-foot) Jebel al-Dukhan mountain, which straddles the border of Saada and Jizan.

A Yemen government spokesman also denied the Saudi military had carried out attacks inside Yemen territory.

Residents were evacuated from villages around Jebel al-Dukhan when the fighting began and relocated to tent camps further away from the border, according to reports.

The London-based Saudi-owned newspaper Asharq al-Awsat reported four Saudi women from one family were killed when their border region home was shelled in cross-border shooting.

Pictures on the local -Jazannews- website showed several Saudi village homes heavily damaged by alleged rebel mortar fire.

Meanwhile other media reports said 40 rebels had surrendered to Saudi forces.

The Yemen government launched an intense military campaign against the rebels on August 11 that has left hundreds dead or injured and sent tens of thousands of people in the region fleeing their homes.

Saana accuses the rebels of seeking to restore the Zaidi imamate that ruled in Sanaa until its overthrow in a republican coup in 1962 that sparked eight years of civil war.

But the rebels accused the Saudis of permitting Yemeni troops to operate against them from inside Saudi territory.

Saudi Arabia's overt involvement has raised concerns among some experts that a "proxy war" is developing between regional rivals Riyadh and Tehran.

Yemen president Ali Abdullah Saleh -- who himself has Zaidi roots -- is heavily supported by the Saudi government. Meanwhile Sanaa accuses Iran of backing the rebels.

On October 28 Yemen said it had arrested five Iranians on a boat loaded with weapons allegedly destined for the Zaidis.

The United States said late Thursday it was "concerned by the expansion of the conflict along the Saudi-Yemeni border."

- It's our view that there can be no long-term military solution to the conflict between the Yemeni government and the rebels - State Department spokesman Ian Kelly said.