ATHENS, Greece - Greek police cleared an immigrant camp in the western port city of Patras on Sunday where hundreds of mostly Afghans had been staying in squalid conditions hoping to sneak on to Italy-bound ferries.

Bulldozers moved in around dawn to clear makeshift structures and trash that had been piling up. A fire broke out but was put out after an hour or so. By afternoon, the area had been completely cleared.

Police said they arrested several dozen illegal immigrants, police said. Those who had valid papers were taken to local hotels and 44 underage migrants were sent to a camp near the border with Albania.

"The illegal immigrants will be dispersed in camps around Greece pending deportation," a Patras police spokesman said on customary condition of anonymity.

The roundup of the immigrants proceeded peacefully, although at least five makeshift bombs exploded in Patras early Sunday, damaging three cars, a bank ATM and the entrance to a court. Police said these were the work of self-styled anarchists, apparently in support of the immigrants.

Left-wing parties denounced the "military-style" operation and the "barbaric" conduct of the police, although there were no confirmed reports of police violence.

The makeshift camp had been in place for more than a decade and housed well over 1,000 refugees at its peak. Initially populated with Kurdish refugees, it became a haven for Afghans after the Sept. 11 attacks.

Patras residents had long clamoured for the camp to be removed. The refugees were well aware of the authorities' intention to clear the camp and had started abandoning it since April, said Christos Papaioannou, Doctors Without Borders field co-ordinator for Patras.

At the time of Sunday's intervention, about 300 remained and many slipped out just before police moved in.

Local authorities estimate that there are now about 800 migrants in Patras, down from a peak of more than 4,000.

Greece had already seen a major wave of immigrants from Albania and Eastern Europe in the 1990s, and is now experiencing a second wave from Africa, the Middle East and Afghanistan. Immigrants, once very rare, now account for more than 10 per cent of Greece's population of 11 million.