The explosion on Saturday targeted pilgrims travelling by bus to observe a ceremony that marks the death of Imam Hassan al-Askari, the 11th revered Imam for Shias.
“All of the victims inside the bus were Iraqi pilgrims, and casualties included people outside the bus as well,” AFP reported.
Samarra hosts the shrine of Imam Hassan al-Askari who died in 874 A.D. The shrine is regularly visited by Shias through out the year.
An explosives-laden vehicle went off near worshippers in the small Shia town of Dujail, in Salahudin Province on Thursday killing nine people and wounding 43 others.
Al-Askari mosque was also attacked in 2007 and 2006 leaving thousands of people dead in Samarra.
Analysts believe the recent wave of violence which has hit Iraq is a plot devised in Washington to create a sense of false insecurity to provide a pretext for the extension of US military stay in the oil-rich country beyond the December 2011 deadline.
According to Opinion Research Business, since the US-led forces invaded Iraq in 2003 more than 1 million civilians have been killed and about 5 million children have been orphaned.