A suicide bomber struck a crowded cafe in one of Iraq's most restive provinces Friday night, killing 21 people in the deadliest attack here in more than a month. The bombing, in the eastern town of Balad Ruz in Diyala province, highlighted fears that insurgents were exploiting the political deadlock to start new rounds of bloodletting and further undermine faith in the government. Shootings, small-scale car bombings and the assassinations of security officials have continued in recent months, even as overall violence has declined from the worst levels of the war, when more than 2,000 Iraqis were being killed each month. Now, stretches of relative calm are often punctuated by deadly attacks, such as the cafe bombing Friday night. The bomber detonated a belt of explosives, the police said, striking the cafe at its busiest hour, when it was bustling with young men sipping tea and smoking cigarettes. The blast blew body parts into the street and started what one survivor, Ahmed Khalis, described as a 'fountain of fire' inside the building. Witnesses said flames reached into the night sky as rescuers tried to pull survivors to safety. 'It can't be imagined,' said Capt. Muhammad al-Rubai, a police official in Diyala province. Thirty people were wounded, many seriously, and officials said the victims included one member of a local governing council. No group immediately claimed responsibility, though one political analyst in the area, Jihad al-Bakri, said the bombing resembled attacks that had been tied to al-Qaida in Mesopotamia. The area where the attack occurred is largely populated by a sect of Kurds who are Shiite Muslims. Most Kurds are Sunnis. Diyala province, which is northeast of Baghdad, straddles Iraq's sectarian and ethnic fault lines. In recent months, it has been the site of deadly bombings of homes, convoys and government buildings, as well as the assassinations of members of the Awakening Movement, an American-supported group of Sunni militias. At a hospital in Balad Ruz, friends and family members walked from bed to bed searching for loved ones. Survivors described being engulfed by flames and said they did not know why they had been attacked. 'Almost everyone who was in the cafe were young guys, and they were jobless,' said Hussein al-Utabi, 22, whose legs were injured. 'It was a massacre.' It was one of the deadliest days in Iraq since bombings in Baghdad and the western city of Fallujah killed at least three dozen people last month. Those attacks occurred on the heels of the U.S. military's official declaration of an end to combat operations in Iraq. Also on Friday, the country's ever shifting political situation grew more complicated after a Kurdish opposition party announced that it was breaking from a larger Kurdish alliance. Members of Iraq's two leading political coalitions, which finished neck and neck in national elections in March, have been trying to court favor with the Kurds, who could be kingmakers in determining which political group controls the new government. The elections did not produce a clear winner, and members of competing political parties have spent the last seven month jockeying for influence and support with different factions in Iraq and abroad, but they have failed to reach a deal. 