Taliban suicide bombers have attacked a US base in Afghanistan, killing at least five people, and sparking a two-hour battle with American forces.
Militants drove two vehicles packed with explosives at the gates of Jalalabad Airfield before American helicopters fired on the attackers.
A guard said that after the initial explosion the airport had come under fire from rocket-propelled grenades, mortars and small arms.
According to an Afghan security official, three Afghan guards were killed in the fighting along with two university students who were caught up in the battle.
A number of Nato's International Security Assistance Force (Isaf) troops were wounded.
A local police official said nine militants were involved in the raid, three were killed by the car explosion and the remaining six were gunned down in the fire-fight that followed.
Lt Col Hagen Messer, a spokesman for Isaf, said: "We can confirm insurgents, including multiple suicide bombers, attacked Jalalabad Airfield this morning. None of the attackers succeeded in breaching the perimeter.
"The final assessment of what happened this morning is not yet complete, but initial reports indicate there were three suicide bombers,"
A Taliban spokesman, Zabiullah Mujahid, claimed responsibility for the attack on Sunday morning.
On its website, the Taliban said: "First a fedayee (suicide bomber) mujahid ... detonated a car bomb causing the enemy heavy casualties and losses and removed all the barriers.
"After the attack other fedayee mujahids entered the base ... and started attacking the invading forces in the base."
The airport complex has multiple layers of security, with the Nato base set well back from the first entrance.
A senior Afghan security official said: "First there was a car bombing next to the entrance followed by gun attack by the insurgents.
"They couldn't reach Nato forces and they were killed in the area between the first and second gates."
It was the largest clash at the Jalalabad air base since February, when a suicide car bombing at the gate triggered an explosion that killed nine Afghans, six of them civilians.
The attack highlights the problems facing the coalition forces ahead of the pull-out of more than 100,000 Nato troops in 2014.
The country's president, Hamid Karzai, insists that Afghan security forces have made good progress and will be able to control the country when the troops leave.
However, there are concerns that the Taliban has managed to survive more than a decade of fighting and will stage a surge once foreign forces leave.