KABUL (Agencies) Four Taliban bombers tried to blast their way into an American base in eastern Afghanistan on Saturday, striking before dawn with rocket-propelled grenades and a car bomb and killing two men in the first suicide attack to hit the once-peaceful region in 10 years of war. All four attackers were killed as well as two truck drivers parked nearby, said provincial police chief Gen Mohammad Qasim Jangalbagh. Two Afghan security guards were wounded. The militants failed to breach the gate of the base in Panjshir provinces Rakha district, though they did hit a security tower with a rocket-propelled grenade. The insurgents targeted the US Provincial Reconstruction Team (PRT) facility in Rokha district, Jangalbagh added. The police and the governors office confirmed that it was the first suicide attack in the Panjshir valley since the war began, underscoring the violence being wrought on once-tranquil parts of the country after a decade at war. The Taliban claimed responsibility, saying the attack was launched with a car bomb packed with 600kg of explosives. The rebel group frequently exaggerate their claims. Security for the ethnic Tajik-dominated area once ruled by guerrilla hero Ahmad Shah Massoud was handed over from Western troops to Afghans in July. An explosion which targeted the PRT in Panjshir left two drivers dead and two guards of the PRT wounded, said Jangalbagh. He said the drivers had been bringing fuel supplies to the base when it came under attack. The first suicide attacker detonated his explosives inside his four-wheel drive vehicle while the other three reached the PRT gate and exploded themselves, he said. The Americans are inside their base, and the bodies of the suicide attackers lie at the gate of the PRT, he added. A spokesman for the Nato-led International Security Assistance Force (Isaf) Christopher Pewitt confirmed the incident but had no record of fatalities. We can confirm a suicide attack on the PRT early this morning in Panjshir. There were no casualties to Isaf. Civilians were injured in the blast, he said, without giving further details. Taliban spokesman Zabihullah Mujahid said the insurgents attacked the gate of the base. Five mujahedeen fighters attacked the gate of PRT in Panjshir province and detonated a car packed with 600kg of explosives, he told AFP by phone from an undisclosed location. Nato downplayed the significance of such spectacular strikes on Saturday, presenting figures that showed headline-grabbing assaults account for only 1 percent of attacks in Afghanistan and that militant activity is down overall. Insurgent attacks between January and September were 8 percent lower than the first nine months of 2010, according to figures supplied by a senior official with Nato forces who spoke anonymously because of the sensitivity of the information. But while violent attacks are down overall, assassinations have increased 60 percent for the same period with 131 people killed so far this year, according to the official. And while Nato reports little change in civilian casualties over the nine-month period, figures from the UN show an increase in civilian deaths. Many of the highest profile attacks have been perpetrated by the Haqqani network, a Taliban-allied group operating out of Pakistan, according to Nato. Eleven out of the last 15 attacks in Kabul came from the Haqqanis and were directed and organised out of Pakistan, the Nato official said. Separately, an Estonian soldier serving with Natos Afghanistan force died after a fire-fight with insurgents during a foot patrol, the Baltic states military said Saturday. Corporal Agris Hutrof, 25, died after his unit came under attack in the southern province of Helmand, Estonian military spokesman Georgi Kokoshinski told AFP. The men, who were on patrol, were attacked by anti-government rebels on Saturday morning, Kokoshinski said. The seriously-injured Hutrof and three other wounded Estonian soldiers were evacuated by helicopter to a field hospital, where he died. The lives of the other three men were not in danger.