Taliban insurgents have struck at airport used by NATO using heavy weaponry against the heavily defended compound. Police said three guards at the base had been killed.
Afghan officials said blasts were heard inside the airfield on the edge of Jalalabad city early on Sunday morning.
Three guards at the base were killed, all of whom the AFP news agency claimed were Afghan. A further 14 people were injured, police said. Meanwhile, nine insurgents were reported to have died.
The attack was confirmed by a spokesman for the NATO-led International Security Assistance Force (ISAF), who denied Taliban claims that the insurgents had entered the compound, some 160 kilometers (100 miles) east of the capital, Kabul.
"We can confirm there have been multiple explosions in the vicinity of the Jalalabad airfield," the Reuters news agency reported the spokesman as saying. "None of the attackers succeeded breaching the perimeter."
The Afghan Defense Ministry confirmed there had been rocket attacks followed by two suicide car bombings. Helicopters were used to repel follow-up assaults by the insurgents.
The Taliban claimed that heavy casualties had been inflicted on the NATO troops.
"This morning at 6 a.m. a number of our devotees attacked the major U.S. Base in Jalalabad city and so far have brought heavy causalities to the enemy," the Reuters news agency reported Taliban spokesman Zabihullah Mujahid as saying.
One Taliban website reported that suicide bombers had claimed the lives of troops by detonating a car bomb.
The base, part of an airfield serving the city as a whole, has several layers of security and was attacked on two previous occasions this year, in February and April.
rc/jr (AFP, AFP, dpa, Reuters)