The US and Italian ambassadors have been hurt in a mortar attack launched by suspected Tamil Tiger rebels in eastern Sri Lanka, officials say.
US ambassador Robert Blake was slightly injured
Robert Blake and Pio Mariani were hit after getting off a helicopter at an air base in Batticaloa, where they were to attend a development meeting.
Mr Mariani received hospital treatment for head wounds. Mr Blake had minor injuries and flew back to Colombo.
The Tigers said they were responding to a government artillery attack.
Sri Lankan human rights minister Mahinda Samarasinghe, who was travelling with the two ambassadors and several other diplomats, was unhurt in the attack, officials said.
The incident happened shortly after the helicopter carrying the diplomats landed at Batticaloa. Mortars fired from long range exploded near the aircraft.
At least nine Sri Lankan security force personnel on the ground were hurt, in addition to a civilian.
"The government of Sri Lanka condemns this attack by the Tamil Tigers in the strongest terms," Rohitha Bogollagama, who is accompanying President Mahinda Rajapakse on a week-long visit to China, said in a statement.
"This is a reminder for the international community to take effective measures to eliminate fundraising and weapons procurement by the Tigers in foreign countries."
But the head of the rebel's peace secretariat, Seevaratnam Puleethevan, told the BBC that it is normal practice for the government to inform them in advance if any foreign dignitaries are visiting conflict areas.
"This did not happen," he said, "in fact our forces were responding to an army artillery attack at the time of the visit."
The Tigers say they were not aware of the high-profile visit
The government has admitted that it did not provide advance notice, but military spokesman Upali Rajapaksa told the BBC that this was hardly necessary.
"Bearing in mind the Tigers were sufficiently well-informed to target the defence secretary in December as he moved about in Colombo, how can they credibly claim not to be aware of such a high-powered foreign delegation going to Batticaloa?" he asked.
Soon after the incident on Tuesday, Sri Lankan air force planes bombed suspected Tamil Tiger positions in the east of the country.
In recent months government forces have driven the Tigers from large areas in the east of the country.
The rebels have withdrawn to jungle areas and clashes are continuing, as well as artillery fire.