Two separate car bomb attacks targeting Shia Muslim pilgrims in the Iraqi capital, Baghdad, have killed at least 25 people, officials say.

At least 14 died when the first bomb exploded on a route used by thousands of pilgrims in the Kadhimiya district.

The second blast, which happened nearby a few of hours later, killed at least 11 others, police and medics said.

On Wednesday, a wave of attacks across the country targeted Shia pilgrims, leaving at least 70 people dead.

The Islamic State of Iraq, a Sunni militant umbrella group that includes al-Qaeda, said it was behind those attacks.

A statement posted on jihadist web forums on Saturday called the attacks the "blessed Wednesday invasion" and a "serious blow" to its enemies.

It was the worst single day of violence in Iraq since the last US troops withdrew in December. Since then there has been a marked deterioration in the country's fragile political process.

The most prominent Sunni Arab politician is currently being tried in absentia on terrorism charges. Vice-President Tariq al-Hashemi denies financing death squads told to kill Shia government and security officials.

'Terrorists will not discourage us'
 
Shia Prime Minister Nouri Maliki has also faced calls for a confidence motion in parliament from parties within his national unity government, which have accused him of breaking promises to share power.

Thousands of Shia pilgrims had travelled to Baghdad on Saturday to mark the anniversary of the death of Moussa al-Kadhim, the seventh Shia Imam and great-grandson of the Prophet Muhammad.

The first bomb, which exploded just after 12:00 (09:00 GMT) in the northern district of Kadhimiya, was left in a taxi abandoned on a main road used by the pilgrims visiting the Imam's shrine, police said.

One of the 22 co-ordinated bombings on Wednesday also targeted Shia pilgrims in Kadhimiya, killing seven people. Another blast near pilgrims' food tents in the Karrada district left another 16 dead.

"The terrorists will not discourage us, even if they cut off our bodies into pieces," promised a song played over the Moussa al-Kadhim shrine's loudspeakers on Saturday, according to the Associated Press.