Baghdad, 4 April (AKI) - Tensions in war-torn Iraq have risen after radical Shia cleric Moqtada al-Sadr called for massive anti-US protests to be held on 9 April in the holy Shia city of Najaf, 160 kilometres south of the capital Baghdad.

Al-Sadr has called for all factions, Sunni or Shia to be present at the protest.

Following al-Sadr's announcement, American tanks reportedly surrounded the Shia stronghold of Sadr City on Friday, while American troops were also put on high alert in order to avoid new clashes.

Many families in Sadr City have chosen to leave their homes, spending the night in mosques or public schools fearing renewed clashes.

Iraqi security forces are worried about what could happen during the protests and are taking necessary measures to prevent violence between the protesters and the Iraqi security forces.

Last week's clashes between Shia militants loyal to al-Sadr and Iraqi security forces left over 210 people killed and 600 injured according to government sources, while militants claimed at least 600 people were killed and over 2,000 injured.

During the clashes, al-Sadr called on the government to stop its raids against his militias known as the Mahdi Army, six days after Iraqi forces began an operation against Shia militias in the southern city of Basra.

The fighting between Shia militias and Iraqi security forces ended only after al-Sadr ordered his militiamen off the streets on Sunday 31 March.

According to a report in the New York Times, more than 1,000 members of the Iraqi security forces deserted or refused to fight against al-Sadr's militias, which the report says casts a doubt on the effectiveness of the US-trained Iraqi security forces.