BAGHDAD — Iraqi and U.N. officials toured a bomb-damaged Shiite shrine in northern Iraq yesterday as workers took the first steps in a long-delayed reconstruction — nearly two years after the attack on the famed golden dome became a rallying point for Shiite rage.

Crews in blue jumpsuits and orange helmets picked through mounds of rubble spilling from the mosque in Samarra, about 60 miles north of Baghdad, which became the spark for a vicious cycle of sectarian violence after the February 22, 2006, blast blamed on Al Qaeda in Iraq.

Months of bloodletting between Shiite and Sunni extremists claimed tens of thousands of lives and lurched Iraq toward a civil war. A second bomb attack last year on June 13 toppled the twin minarets, prompting Shiite clerics to step up calls for the reconstruction of the Askariya shrine.

The complex contains the tombs of two ninth-century imams who were descendants of the Prophet Muhammad, and Shiites consider them to be among his successors. An envoy for Iraq’s Shiite-led government, Haq al-Hakim, described the $16 million rebuilding effort as a symbol of national unity at a time when violence is decreasing across most of Iraq.

But the morgue count yesterday showed how quickly bloodshed can return.

Iraqi police reported at least 30 people killed or found dead around the country, including eight beheaded bodies found in Diyala province. It was one of the highest daily tolls in weeks.