BAGHDAD -- Six people were killed and more than 50 were wounded on Saturday when several dozen mortar shells fell on a refugee camp for members of an Iranian opposition group, according to an Iraqi police official.
The camp, on the site of a former American military base near the Baghdad airport known as Camp Liberty, is home to about 3,400 Iranian exiles who are members of Mujahedeen Khalq, or M.E.K., a militant organization. It was removed from the State Department's terrorist list in September after years of intensive lobbying from prominent American politicians and former military officers, who viewed the group as a legitimate democratic alternative to the Iranian government.
In an e-mail sent to news media outlets in Iraq, the military wing of Hezbollah in Iraq, a militant organization believed to have connections to the main Lebanese group and to Iran, claimed responsibility for the attack and warned that others would follow.
Although Hezbollah in Iraq was active during the American military presence there, attacks by the group died down after the Americans left, and its leaders said they would lay down arms and join the political process. But in an ominous sign that a recent spate of deadly sectarian conflicts in Iraq might escalate, the group announced at a recent news conference that it was establishing a militia to fight Sunni groups that had been attacking Shiites. Camp Liberty is meant to be a temporary residence for the Iranian refugees while the United Nations works to find host countries for them. In a statement issued from Geneva, the United Nations high commissioner for refugees, António Guterres, called the attack "a despicable act of violence" and said the residents of the camp were asylum seekers entitled to international protection.
In a statement, the M.E.K. accused the Iranian government and Iraqi forces of being behind the attack, and said the Iraqi government had recently removed the blast walls surrounding the camp, leaving the refugees unsafe. The group said that more than 100 had been injured in the shelling and that its demands to return to its previous location in Iraq, Camp Ashraf, had been ignored.
"The residents and their representatives have warned about a massacre by the Iranian regime and the Iraqi forces," the statement said, "and demanded several times from the secretary general of the United Nations and U.S. officials to return to Camp Ashraf, where concrete buildings and shelters are available."
Ali al-Moussawi, an Iraqi government spokesman, denied that Baghdad was involved, saying the accusation from the M.E.K. "is not the first time when they blame us for everything."
The United Nations demanded that the Iraqi government open an investigation, saying in a statement that Martin Kobler, the United Nations special representative for Iraq, "called on the Iraqi authorities to immediately ensure medical care for the wounded."
The M.E.K. had long resisted leaving Camp Ashraf, on land that had been set aside by Saddam Hussein, the toppled Iraqi dictator, and did so only because the United States made it a condition of dropping the group's terrorist designation. An American official said in August that the M.E.K. had been using Camp Ashraf for paramilitary training.
The group carried out bombings in Iran in the 1970s against the shah's government and later against the Islamic government, causing the death of several Americans, but by most accounts it has not engaged in terrorism in recent years. But Iraq's current government, a close ally of Iran, views the M.E.K. as a terrorist group and wants it out of the country.
This article originally appeared in The New York Times.