A suicide bomber struck in an area between major shrines in the Iraqi Shiite holy city of Karbala on Sunday, causing casualties, an official from one of the shrines said.
Jamal al-Din Shahristani, an official at the Imam Hussein shrine, said an engineer working on a project between the site and the Imam Abbas shrine blew himself up, causing an unspecified number of casualties.
The shrines for the two grandsons of the Prophet Mohammed are among the holiest sites in Shiite Islam, and are visited by hundreds of thousands of pilgrims each year.
Sunni militants frequently target Iraq's Shiite majority in a bid to increase sectarian tension and undermine the country's Shiite-led government.
Though no group has claimed responsibility for the bombing, suicide attacks are a hallmark of Al-Qaeda's front group in Iraq.
Iraq was wracked by bloody sectarian conflict following the 2006 bombing of a Shiite shrine in Samarra, north of Baghdad, but tensions in the country have since decreased.
Though violence has fallen considerably compared to past years, attacks in Iraq still remain common, killing 220 people in February, according to an AFP tally based on security and medical sources.