Isis massacres 100 Shiite pilgrims, mostly Iranians, returning from Kerbala
Iraqi security forces inspect the site of a suicide truck bomb attack, at a petrol station in the city of Hilla south of Baghdad, Iraq, November 24, 2016. REUTERS/Alaa Al-Marjani

Islamic State militants claimed responsibility for a suicide attack in a city south of Baghdad that killed nearly 100 Shiite pilgrims on Thursday night. The attack took place at a petrol station in Hilla in Babylon province, a city about 100 km south of Bagdad where the Shia pilgrims had halted their journey back to Iran from the Shiite holy city of Kerbala.

The victims are mostly Iranians but there are Iraqis and Bahrainis as well among them, Al Jazeera reported. "There are completely charred corpses at the scene," Falah al-Radhi, head of the provincial security committee, said.

Shiites are a frequent target for the Sunni Islamist Isis which considers Shias as apostates. The latest attack took place even as Shia militias are actively taking part in a lethal US-backed Iraqi offensive against the Isis in their former stronghold Mosul.

The victims of Thursday's attack were returning after performing the Arbaeen in Kerbala, which commemorates the 40th day of mourning for the 7th century AD killing of Imam Hussein, a grandson of the Prophet Mohammad.

The petrol station which the suicide attacker had targeted had a restaurant on its premises and it is a familiar stopover for travellers on this stretch. Several buses in which the Shiite pilgrims were travelling went up in flames as the truck bomb exploded.

"The whole place was completely wrecked. It was a massive blast ... When the gas tanker blew up, it also torched several buses and minivans that were carrying the pilgrims," an Al Jazeera reporter at the scene said.

According to the Joint Operations Command in Baghdad, the truck was packed with 500 litres of ammonium nitrate, a chemical compound used in explosive devices.

Iran condemned the latest Daesh attack and said it will continue to support Iraq's fight against terrorism.

"The United States remains steadfast in its partnership with the Iraqi people and government and this attack only serves to strengthen our resolve in defeating ISIL," the National Security Council said in a statement.