The landing zone for helicopters carrying the diplomats and Sri Lanka's human rights minister came under fire Tuesday from Tamil Tiger artillery.
U.S. Embassy officials in Colombo say Ambassador Robert Blake suffered a "superficial wound" that "drew blood" and may have been caused by shrapnel or a rock. Italian envoy Pio Mariani was taken to a hospital where a small piece of shrapnel was removed from his head. The German Embassy in Colombo says its ambassador, Jurgen Weerth, initially reported hurt, was not injured.
Human Rights Minister Mahinda Samarasinghe was giving several diplomats a tour of the restive eastern district of Batticaloa, where government troops last month captured a key Tamil Tiger stronghold.
Sri Lanka's Foreign Ministry calls the incident a deliberate attack targeting foreign diplomats on a humanitarian mission.
The executive director of the Regional Center for Strategic Studies in Sri Lanka, Paikiasothy Saravanamuttu, says if that was the case, it is likely to backfire on the rebels.
"If they want to create a positive image for themselves in the international community, I wonder if they would be firing mortars or rockets or whatever at foreign ambassadors," he said. "On the other hand, there might well be the argument that they wanted to create some kind of dramatic, sensational impact to remind that they are still a force to be reckoned with."
The rebels, who are fighting for a separate homeland for Sri Lanka's Tamil minority group, say they were unaware of the presence of the ambassadors. A Tiger spokesman expressed regret that the diplomats were injured, blaming the government for putting them in harm's way.
Sri Lankan foreign minister, Rohitha Bogollagama, on a visit to Beijing, said the Tamil Tigers had again demonstrated their "terrorist nature" by launching the attack.
He said the attack was a reminder to the international community to "take effective measures to eliminate fundraising and weapon procurement" by the Tigers abroad, and wished the injured a speedy recovery.
Sri Lanka's Defense Ministry says seven security personnel at the air base were wounded.