A bomb attack killed about 25 people in Syria on Friday, while a wave of attacks against Shia Muslims killed at least 78 people in Iraq on Thursday.

A suicide bomber killed about 25 people and wounded 46 in Damascus, Syria's state news agency SANA said.

Syrian state television showed body parts, bloodstains and broken glass from the blast in the central Maidan district. Several riot police shields could be seen in a wrecked bus, which was among several damaged vehicles.

SANA said 10 people had been killed and body parts of about 15 more had been found.

On December 23 at least 44 people were killed by what Syrian authorities said were two suicide bombings that targeted security buildings in the Syrian capital.

Those attacks occurred the day before the arrival in Damascus of the head of the Arab League observer mission.

Footage of Friday's blast on Syria's semi-official Addounia TV showed yellow tape stretched around the wrecked bus and cars with smashed windows in a street. People collected body parts on blue plastic sheets amid pools of blood and scattered shoes.

Arab monitors in white baseball caps and orange vests inspected the area, taking notes and filming. The local police station was visible, apparently untouched by the explosion.

The TV showed crowds of angry locals gathered at the scene, chanting "God, Syria and Bashar only" and "God protect the army" and "With blood and soul we sacrifice for you Bashar."

A woman named Umm Mohammed said those behind the blast were attacking the security forces who protect Syrians. "They (protesters) say they want freedom, this here is freedom, not those children of saboteurs, God curse them," she said.

The monitors confirmed they had visited the scene. "We are only here to observe and document," one of them said.

In Iraq, the death toll from the multiple bomb attacks that rocked southern parts of country and the capital Baghdad has risen to 78, Press TV reported. 

The attacks began during morning rush hour on Thursday when explosions struck the capital's mainly Shia neighborhoods of Sadr City and Kazimiyeh, killing around 30 people. 

Around 48 people were killed several hours later in another bombing incident in the city of Nassiriya, 320 kilometers southeast of Baghdad. 

Nassiriya attack targeted a group of Shia pilgrims walking to the holy shrine city of Karbala for the commemorations marking the 40th day after the martyrdom of the third Shia Imam, Imam Hussein (PBUH). 

Thursday's attacks were the deadliest Iraq has witnessed in the past month, following the multiple bomb explosions of December 22, 2011 where dozens of people were killed in nine neighborhoods in the capital.