Gunmen who stormed the University of Anbar in the Iraqi city of Ramadi and briefly took students and staff hostage have now deserted the campus, police sources have told Al Jazeera, while fighting between security forces and rebels in a northern city killed 59 people.

The hostages fled to safety after the armed men left and security forces then secured the area.

There were no reports of casualties in Saturday's incident, which the police blamed on the Islamic State of Iraq and the Levant (ISIL) group.

In a separate incident earlier in the same city on Saturday, a car bomb exploded as an army convoy passed, killing three people and injuring 10, police sources and a local journalist said.

Al Jazeera's Imran Khan, reporting from Baghdad, said that the taking of hostages was not a usual ISIL tactic.

"What they do is the kind of attack we saw a few hours earlier, a hit-and-run on an army convoy," he said.



"Ramadi seemed to have quieted down. There seems to be a ratcheting up right now from ISIL fighters."



Suicide attacks

ISIL, which grew from the remnants of a now defunct al-Qaeda affiliate and other Sunni-led armed groups, have controlled parts of Anbar province, including the city of Fallujah and parts of Ramadi, since late December.

Iraq is currently grappling with its worst surge in violence since the sectarian bloodletting of 2006 and 2007, when the country was pushed to the brink of civil war despite the presence of tens of thousands of US troops.

Fighting broke out this week in the cities of Samarra and Mosul, which was also hit by suicide attacks.

In Mosul, heavy fighting between rebels and security forces entered its second day on Saturday, killing 21 police and 38 rebels, an officer and mortuary employee said.

Fighting erupted in Mosul on Friday morning and continued into the night, according to the AFP news agency.

Police officials said 65 people were killed by shelling in Mosul on Friday as the military tried to push rebels from their positions.

Armed men took control of several districts in Samarra on Friday before being pushed back.



But sources in the city told Al Jazeera that ISIL fighters control areas during the night before melting away in the day when the military moves back in.

Anger fuelling violence

The latest violence has been fuelled by Sunni Muslim anger at the Shia-led government in Baghdad, as well as the civil war in neighbouring Syria.

ISIL has carried out scores of deadly attacks on both sides of the border and imposed a strict form of Islamic rule in territories under its control.

More than 900 people were killed in Iraq last month, according to figures separately compiled by the United Nations and the government.

More than 4,000 have been killed so far this year, according to AFP news agency figures based on security and medical sources.