The revelation, along with a photograph that purports to show the wound, added further credence to accusations cluster munitions had been used during the final months of the war.
Many of the thousands wounded in the government offensive against ethnic Tamil rebels in northern Sri Lanka also had burns consistent with those caused by incendiary white phosphorus bombs, the medical worker said. He spoke on condition of anonymity out of fear of reprisals from the Sri Lankan government.
The accusation is likely to increase pressure for an international war crimes investigation into the final, bloody stage of the quarter-century civil war that ended in 2009 when the government overran the Tamil Tiger rebels' stronghold. A report last year by a U.N. panel of experts said tens of thousands of civilians were killed in the last months of the war and found credible allegations of war crimes by both government forces and the rebels.
Sri Lanka's government has repeatedly denied using either white phosphorus or cluster munitions in the war zone, where tens of thousands of civilians were trapped in a tiny spit of land along with rebel fighters.
In a statement Friday, it called the accusations "baseless."
"Neither 'cluster munitions' nor illegal weaponry were used," it said.
However, a U.N. demining expert separately wrote an email earlier this week saying he had identified unexploded cluster bomblets in the former war zone while he was looking into the death of a boy who had been foraging for scrap metal.
"These ongoing reports of cluster bombs being used in Sri Lanka are worrying, and we're taking them seriously," said Laura Cheeseman, director of the Cluster Munition Coalition, which advocates for the elimination of the weapon. "Experts within the CMC network are investigating further as we speak, and we encourage the Sri Lankan government to do likewise."
The medical worker said local U.N. staffers had told him in early February that they had found shrapnel from cluster munitions around a hospital in Puthukudiyiruppu.
The facility was later moved to a makeshift hospital in the village of Putumattalan, where patients began speaking of being wounded by cluster munitions, which make an unmistakable sound, a loud explosion followed by a burst of tiny blasts, the worker said. But medical officials could not find evidence of the munitions because the wounds were so badly infected, the worker said.
Then, in late March or early April, a man came in with a wound in his lower leg. After the medical staff cleaned the wound, they discovered a small unexploded bomblet from cluster munitions wedged into it, the worker said.
The staff amputated the man's leg below the knee, then took it, along with the bomb still inside and threw it into an empty field because there was no safe way to dispose of it, the worker said.
A photograph provided to the AP showed a lateral gash in a man's leg just below the knee with a greenish metal cylinder embedded in the tissue.
Technical experts shown the photo said they were unable to tell whether or not it was a bomblet.
Cluster munitions are packed with small "bomblets" that scatter indiscriminately and often harm civilians. Those that fail to detonate often kill civilians long after fighting ends. They are banned under an international treaty that took effect in August 2010, after the Sri Lankan war ended.
Patients also came to the clinic suffering burn wounds consistent with the use of white phosphorus, said the medical worker, who inspected a nearby area after a bombing and found it charred and aflame.
White phosphorus is not specifically banned under international law, but human rights groups says its use in heavily populated civilian areas could amount to a war crime.
The U.N. Human Rights Council passed a resolution last month urging a probe into allegations of summary executions, kidnappings and other abuses during the war. Human rights groups have said the government was incapable of conducting a fair investigation into its own behavior and called for an international probe.
The war pitted Tamil separatists against a government dominated by the Sinhalese majority, which has marginalized minority Tamils for decades.
AP