CAIRO, Egypt (AP) _ Police swept through a poor Cairo district again Thursday rounding up Muslim militants in the strongest effort in more than a decade to crush a violent campaign to overthrow Egypt's secular state.

Militants threw firebombs at a police car, wounding two officers, and firebombed four video rental shops during the sweep of Imbaba, considered the stronghold of the fundamentalist al-Gamaa al-Islamiya, or Islamic Group.

Police said 162 people were arrested overnight and Thursday. A member of al-Gamaa, who telephoned The Associated Press from a hideout in Imbaba, claimed no more than 60 Muslim militants were arrested.

Police said 573 suspects have been detained since the government launched the crackdown Tuesday. It has deployed about 14,000 policemen and 100 armored personnel carriers in the operation.

The crackdown was not expected to end the militants' campaign, because they have an extensive underground operation that can operate even when their leaders are in jail.

Police officials said the operation will continue - and escalate if necessary - until all suspected militants are arrested.

Al-Gamaa, the largest fundamentalist group, has about 200,000 members and sympathizers nationwide, including about 10,000 militants. The government claims they are backed by the Islamic regimes in Iran and Sudan.

The extremists want to overthrow President Hosni Mubarak's secular government and replace it with a Muslim theocracy. President Anwar Sadat, Mubarak's predecessor, was assassinated by Muslim extremists in 1981.

The current operation is the most extensive against extremists since a crackdwon after Sadat's killing left about 80 dead and thousands arrested.

The militants have stepped up their attacks this year against their usual targets - Christians and police - and have begun targeting tourists to damage Egypt's image abroad and cut its main source of foreign currency. Since January, 78 people have died in the violence, including one British tourist.

The Imbaba sweep was part of a nationwide crackdown that started after militants shot at a tourist bus in southern Egypt on Nov. 12, wounding five Germans. Five suspects have been arrested in that attack.

Hisham Mubarak, a lawyer for the extremists, said the militants might escalate their attacks, possibly against tourists or embassies.

''Their response until now has been limited,'' he said. ''If (police) continue their siege of Imbaba and keep up the detentions, al-Gamaa might think of moving their attacks to the heart of Cairo.''

On Wednesday, Mubarak ratified death or prison sentences imposed by a military tribunal last month on 39 extremists despite another court's ruling that nullified their convictions.

Seven of the eight sentenced to death are fugitives. Thirty-one people got jail terms ranging from one year to life for trying to overthrow the government or destablize it by terrorist methods.