In a second day of major bloodshed, two suicide bombers wearing explosive vests blew themselves up at the gates of a Shi'ite Muslim shrine in Baghdad on Friday, killing 60 people, Iraqi police said. The attack was the deadliest single incident in Iraq since 63 people died in a truck bomb blast in Baghdad on June 17 last year, and came amid growing concerns that a recent drop in violence might turn out to have been just a temporary lull. At least 125 people were wounded in the apparently coordinated blasts at the Imam Moussa Al-Kadhim shrine in the Shi'ite neighborhood of Kadhimiya, police said. The attacks took place as hundreds of worshippers gathered to pray. Many of the dead and wounded were Iranian Shi'ite pilgrims. One of the bombers blew himself up in a group of dozens of Iranian pilgrims, a wounded man at a nearby hospital said, asking not to be named. Police said the attackers approached two different gates to the shrine, which has been a frequent target in the past. The blasts followed two suicide bombs on Thursday, one in Baghdad and the other in the northeastern province of Diyala, in which at least 89 people died. Most of the 57 dead in Diyala were Iranians, who have flocked to Iraq's Shi'ite holy sites in the millions since Saddam Hussein was ousted in 2003. “The incident (in Iraq) yesterday was a very, very hateful example of those who harm religion in the name of religion,” influential Iranian cleric and former president Ali Akbar Rafsanjani told worshippers at Friday prayers. “We feel sorry for the Iraqi people because such corrupt groups have penetrated into Iraq. “We also criticize America for not having the serious will to preserve Iraq's security,” Rafsanjani added. While violence in Iraq has fallen dramatically over the past year, insurgent groups such as Al-Qaeda still carry out frequent attacks. The latest attacks coincide with growing fears of a resurgence in violence as US troops prepare to pull out of Iraqi cities in June, ahead of a full US withdrawal by the end of 2011, and amid doubts over the effectiveness of Iraqi forces. A national election at the end of the year has also heightened apprehensions as political parties and armed groups jostle for dominance of the oil-producing nation. Al-Baghdadi myth? On Thursday, Iraqi authorities announced the arrest of a leader of an Al-Qaeda-linked insurgent group. But neither they nor the US military were able to confirm on Friday that the person was Abu Omar Al-Baghdadi, the purported head of a group called the Islamic State of Iraq (ISI).