A suicide bomb attack at a market in the southern Iraqi city of Najaf has killed at least 35 people and injured more than 90 others.
The streets near the shrine were packed when the attack happened
Reports say the bomber detonated a belt of explosives at a police checkpoint.
The attack occurred near the Imam Ali shrine, one of the most sacred Shia Muslim sites. A Sunni insurgent group claimed it had carried out the bombing.
In a separate incident, at least six people were killed by a bomb in a restaurant in Baghdad.
That attack, in the southern part of the capital, comes a day after Baghdad mortuary officials said they had received 1,855 bodies in July - the highest monthly figure yet.
At least three police commandos, including a senior officer, were also killed in clashes with gunmen in southern Baghdad.
Pilgrims and shoppers
Najaf, a predominantly Shia city 160km (100 miles) south of Baghdad, has been the scene of some of the most deadly sectarian attacks since the US-led invasion of Iraq in 2003.
The city's Imam Ali shrine is a key centre of pilgrimage.
The BBC's Mike Wooldridge in Baghdad says the streets leading to the shrine were packed with pilgrims and shoppers in the middle of the morning when the bombing occurred - on the anniversary of the death of Imam Ali's daughter.
The bomber was reported to have detonated his explosives at a checkpoint at the entrance to the grand market which leads to the shrine.
The Sunni insurgent group Jamaat Jund al-Sahaba (Soldiers of the Prophet's Companions) said it was behind the attack, in a statement posted on an Islamic website.
The statement's authenticity could not be verified.
The offices of Iraq's most senior Shia cleric, Grand Ayatollah Ali Sistani, are close to the site of the attack.
Our correspondent says Najaf and its twin city of Kufa are tightly controlled by Shia guards.
The last major attack of this kind was a suicide car bombing near a Shia shrine in Kufa in July, which killed more than 50 people.