By Paul Handley

RIYADH, Nov 04, 2009 (AFP) - A clash between Saudi forces and Yemeni rebels left one Saudi and one rebel dead, the two sides said on Wednesday, as Yemen's five-year-old insurgency spilled over the frontier for the first time.

Riyadh said that one border guard was killed and 11 others wounded when armed infiltrators attacked them inside Saudi territory in the mountainous border region of Jabal al-Dukhan, the official SPA news agency said.

The attack took place just over the frontier from an area where Yemeni forces have been fighting Zaidi Shiite rebels for weeks.

"Armed men infiltrated at Jabal al-Dukhan... and opened fire on the border patrol with an assortment of weapons, killing one and injuring 11 others," SPA reported citing an unidentified government spokesman.

A Saudi interior ministry official contacted by AFP said he had no information on whether any of the attackers were wounded or captured in Tuesday's attack, and said there was still no formal word on who was behind it.

But an internet website close to the rebels also reported a clash in the Jabal al-Dukhan area and said that a rebel fighter had been killed.

"The Saudi border guards fired on one of our vehicles, leaving one a martyr and one wounded," the website said.

It was the first reported clash between Saudi forces and the rebels since the Yemeni government launched an all-out air and land offensive against them in the country's far north in August.

The campaign has left hundreds dead or wounded and sent tens of thousands fleeing their homes, many into makeshift camps.

The rebels have been backed up against the border and have accused Saudi forces of both allowing Yemeni troops to cross Saudi territory to circle around behind them and of firing on them themselves.

In an on-line statement on Wednesday, the rebels warned the Saudis of the "grave" consequences of their "interference in the Yemeni fighting.

"If the Saudi regime continues to attack us, we will defend ourselves," they said.

Rebel spokesman Mohammed Abdel Salam told AFP that their fighters fired back after being fired upon by the Saudis on Tuesday.

He said the rebels had always tried to avoid any clash with Saudi forces.

On Monday the rebels, also known as Huthis, accused Riyadh of permitting Yemeni troops to launch attacks against them from a Saudi security installation in Jabal al-Dukhan.

"We advise the Saudi regime to remain impartial and not allow the Yemeni army to use its territories to attack us, because we would otherwise be forced to retaliate," the rebels said in an e-mailed statement received by AFP.

The Saudis have steadfastly denied any involvement in the fighting but clashes so close to its territory have raised deep concerns in Riyadh, which has tightened up security on the frontier.

Diplomats say Riyadh probably is providing support to Sanaa, but say it is more likely to be financial, intelligence and logistical help.

The Sanaa government has accused Shiite Iran of backing the rebels and last week announced the seizure of five Iranians on a boat loaded with arms in the Red Sea.

But a Saudi official speaking on condition of anonymity said there was little evidence that Iran was actively supporting the rebels.

The Zaidis form the majority community in the far north but are a minority in mainly Sunni Yemen.

The Yemeni authorities accuse the rebels of seeking to restore the Zaidi imamate that ruled in Sanaa until its overthow in a republican coup in 1962 that sparked eight years of civil war. The rebels deny the charge.

pmh/kir

© Copyright AFP 2009.