Iraqi Prime Minister Nouri al-Maliki said Thursday that Syria was sheltering armed groups wanted for cross-border attacks, forcing him to appeal to the United Nations for help in stopping what he called a hostile act.Relations between the countries have been particularly tense since a pair of truck bombings in August outside the foreign and finance ministries in Baghdad that killed about 100 people. Iraq, which has blamed an alliance between al-Qaida in Iraq and Saddam Hussein's outlawed Baath Party, wants Syria to hand over several suspects it says are based there.Maliki, who has faced criticism for security lapses that aided the bombers, met with a group of European and Arab ambassadors Thursday to press his case that those who plotted the Aug. 19 attacks are based in Syria.It is an especially sensitive issue for Maliki, who has used overall improvements in security as his main campaign talking point before January's national elections. The ministry bombings shook people's confidence at a time when his government is trying to show it can ensure security now that most US forces have withdrawn from urban areas."Why is there this insistence on harboring armed groups and persons wanted by Iraqi jurisdiction?" the prime minister said, referring to Syria's refusal to deliver suspects. His comments were released by his office after the meeting.Syria, which has demanded to see proof of Iraq's claims, accuses Maliki's government of seeking to exploit the ministry attacks to press demands for the handover of Iraqi opposition figures living in Damascus.Both countries have recalled their ambassadors over the dispute, which came as relations between the neighbors were thawing after decades of tension.Syria is home to a number of Iraqis who were mid-ranking and senior members of Saddam's Baath Party, and Iraqi officials say Damascus allows them to live and engage in political activity in Syria.Maliki said such groups should not be allowed by the countries hosting them to interfere in Iraq's internal affairs, especially after the start of the American troop withdrawal."Some neighboring countries considered the presence of multinational forces as harmful to their national security and they started to interfere with the pretext of resisting the occupation," he said. "But, after the withdrawal of US forces, this situation has become unacceptable and we consider it a hostile act."Even prior to the August attacks, Iraq had asked Syria to cooperate in stopping the activities of Baath Party figures, but instead that activity increased, Maliki said."We are now compelled to request the [UN] Security Council to form an international tribunal because Iraq is facing a serious threat from neighboring countries," the prime minister said.Iraq wants the formation of such a tribunal that would pressure Syria to deliver suspects in the August bombings.Overall, violence has eased across Iraq, though attacks have persisted in cities like Baghdad and Mosul in the north. Three roadside bombings in the Mosul area on Thursday killed one Iraqi policeman and wounded three people.Also Thursday, a car bomb apparently targeting the leader of Iraq's largest Sunni political party wounded four people northeast of Baghdad, police said. The politician escaped unharmed.Police said the car, parked near a restaurant in the city of Baqouba, exploded two minutes after a convoy passed by with the leader of the Iraqi Islamic Party, Osama al-Tikriti, and other officials. Four civilian bystanders were wounded in the blast, which destroyed a number of shops along Baqouba's main street, said police Capt. Ghalib al-Karkhi.