A court has ordered two policemen to be held in jail pending trial for a teenager's fatal shooting, which has sparked five days of rioting in Greek cities.

One officer has been charged with murder for allegedly shooting dead 15-year-old Alexandros Grigoropoulos. The other has been charged as an accomplice to murder. No trial date has been set.

A defense lawyer says the fatal bullet ricocheted off a wall before striking the schoolboy in the heart.

Earlier Wednesday, protesters attacked Athens' main courthouse with firebombs during a hearing for the two officers. Riot police fired tear gas. At least two people were hurt.

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Riot police and youths also clashed in the city center during a protest by more than 10,000 people at government economic policies.

The strike and demonstrations were scheduled before the riots broke out but have been fueled by anger at the handling of the riots by the government of Prime Minister Costas Karamanlis. Schools, public services, hospitals and flights have been shut down by the strike.

"This country is not being governed. The government can no longer convince anyone," senior Socialist party member Evangelos Venizelos said in Parliament. "There is no way Mr. Karamanlis can come back from this."

The policemen's lawyer, Alexis Cougias, told reporters that a ballistics examination showed that 15-year-old Alexandros Grigoropoulos was killed by a ricochet and not a direct shot. One of the officers had claimed he had fired warning shots and did not shoot directly at the boy.

"Unfortunately this tragedy is the result ... of an act by the policeman to fire into the air. The bullet ricocheted, we have an entry wound from above," Cougias told reporters outside the courthouse. "It proves irrefutably that it was a ricochet."

He said the ballistics report was not yet complete but said he had been informed of its contents by authorities. There was no comment from prosecutors, who do not make public statements on pending cases.

Karamanlis' government holds a single-seat majority in the 300-member parliament. It has faced growing opposition over changes to the country's pension system, privatization and the loosening of state control of higher education, which many students oppose because they feel it will undermine their degrees.

The government's support dropped lower as gangs of youths marauded through cities across the country, torching businesses, looting shops and setting up burning barricades across streets.

The clashes in central Athens escalated into running battles through the city center, with masked youths pelting police with rocks, bottles and blocks of marble smashed from the Athens metro station entrance. The youths shattered windows newly replaced after four nights of rioting.

"The government wanted us to postpone this protest, but they are the ones who have to do something to stop this violence and to improve the quality of our lives," said one demonstrator, drama student Kalypso Synenoglou.

High-school students chanting "Cops! Pigs! Murderers!" clapped and cheered each time a riot policeman was hit by a rock. At least one person was hurt.

Clashes also broke out during demonstrations in the northern cities of Thessaloniki and Kavala.

Storeowners have accused authorities of leaving their businesses unprotected as rioters smashed and burned their way through popular shopping districts. Although police have responded when attacked by rock- and Molotov cocktail-throwing protesters, they held back when youths turned against buildings and cars.

But Karamanlis has ignored mounting calls for him to resign and call early elections.

An opinion poll for the conservative daily Kathimerini published Wednesday found 68 percent of Greece believe the government mishandled the crisis — including nearly half of respondents who voted for Karamanlis' conservative party in general elections last year. Only 18 percent approved.

The Public Issues survey was based on a sample of 478 people questioned Monday and Tuesday and had a 4.5 percent margin of error.

Greece has a long legacy of activism; it was a student uprising that eventually brought down a seven-year military junta in 1974. Tensions persist between the security establishment and a phalanx of deeply entrenched leftist groups that often protest globalization and U.S. foreign policy in the Middle East and elsewhere.

The groups have now evolved into various mainly youth factions that claim to fight trends ranging from globalization to police surveillance cameras. Their impact is usually limited to graffiti and late-night firebomb attacks on targets such as stores and cash machines.

Amnesty International accused Greek police of heavy-handed tactics against protesters, saying police "engaged in punitive violence against peaceful demonstrators" instead of focusing on rioters.

Authorities are investigating reports officers used their pistols to fire warning shots in the air during Tuesday's riots.