"A wing of our Preah Vihear Temple has collapsed as a direct result of the Thai artillery bombardment," a commander based near the 900-year-old temple was quoted as saying by Cambodia's Press and Quick Reaction Unit (PRU) of the Office of the Council of Ministers.

"The Thai army began shooting at us first, we are taking self- defense and retaliatory measures, now," the commander said, stressing that the Thais had not honored the ceasefire of Saturday.

PRU did not give the name of the commander.

The commander also said that the Thai army has used gas shell as they fired 130 mm artillery rounds at Cambodian soldiers. Thai army resumed heavy shelling on Cambodia's troops around 6:40 p.m., he said.

The newly erupted fighting near Preah Vihear Temple between Cambodian and Thai troops stopped at about 9:40 p.m. local time, lasting nearly three hours.

This is the third military clash after the last two conflicts on Feb. 4 and Feb. 5.

So far, there was no immediate report about the deaths and wounds.

The fighting has burst out at Phnom Trap hill and Veal Intry situated 1,600 meters and 1,120 meters respectively from the border inside Cambodian territory towards the Beehive area near Preah Vihear temple.

Colonel Chan Narun, who stations at the Preah Vihear temple, said "the fighting this time is likely bigger in scale than the two previous clashes -- the fighting is spread larger along the border," he said. "Heavy weapons including rockets, machine guns and mortars, artillery have also been used in the exchange fire."

He said "locals have been evacuating from the areas."

Meanwhile, Thai troops have been reinforced in many other parts along the borders, said Cambodian solders in the battle.

According to Thailand's The Nation, the clash broke out just before 7 p.m. local time.

The report quoted Colonel Sansern Kaewkamnerd, the spokesman of Thai Royal Army, as saying that the Cambodians fired first.

There were no immediate reports of casualties.

The last two clashes on Friday and Saturday left two Cambodian soldiers dead, but one of whom was not killed by the bullets from Thai troops, but his own accidental bullet, and also another Cambodian civilian was killed on the first day of the clash.

In addition to the deaths, 20 others were injured. For the Thai side, 32 were killed in Cambodian territory, and many others injured, according to the spokesman for Cambodian council of ministers Phay Siphan on Sunday afternoon.

The border between Thailand and Cambodia has never been completely demarcated and the issue of the Preah Vihear temple has been an age-old dispute.

Cambodia's Preah Vihear temple was enlisted as World Heritage Site on July 7, 2008. Just a week after the enlistment, Cambodia and Thailand have had border conflict due to Thai claim of the ownership of 1.8 square miles (4.6 sq km) of scrub next to the temple, triggering a military build-up along the border, and periodic clashes between Cambodian and Thai soldiers have resulted in the deaths of troops on both sides.