ATHENS - Greek Prime Minister Costas Karamanlis pledged on Tuesday to fight corruption after 11 days of violence triggered by the police killing of a teenager and fueled by public discontent at scandals and a slowing economy.

Karamanlis said helping the needy was a priority but his options were restricted by the country's huge debt burden, made worse by the riots that quickly spread across Greece and to some other European countries.

Greece's worst violence in decades was sparked by the December 6 shooting of a 15-year-old but fed off anger at high youth unemployment and unpopular economic measures as the global crisis buffets the country's 240-billion-euro ($327.9 billion) economy.

"Long unresolved problems disappoint young people -- the lack of meritocracy, corruption in everyday life, a sense of social injustice," Karamanlis told his parliamentary team.

"The fight against them is hard and constant and we are committed to it."

Karamanlis, under fire for his hands-off reaction to the riots, said he had underestimated the public backlash and the scale of a monastery land scandal that has rocked his government for months.

A parliamentary investigation concluded on Monday failed to seek anyone's prosecution for the deal, where a wealthy Mount Athos monastery got valuable state property in exchange for cheap rural land, costing the state millions of euros.

With more protest marches planned as the 2009 budget goes to parliament this week, Karamanlis said no new taxes will be imposed and planned income tax cuts will go ahead as planned: "Our top priority is to support those hurt the most."

But he warned against high expectations, saying Greece will spend 12 billion euros, about 5 percent of GDP, just to service its debt in 2009. "This debt is a huge burden that reduces the government's flexibility at a critical time," he said.

Reshuffle possible

Political analysts said the riots brought the prospect of snap elections closer and that Karamanlis would sacrifice some ministers to inject new blood into his conservative government.

"Today the prime minister accepted partial political responsibility," Theodoros Livanios, director of political and social research at Opinion, said.

"I expect that Karamanlis will soon announce a reshuffle of his government and then will wait to see the success of this."

In bond markets, the spread between Greek debt and German benchmark bonds -- a measure of perceived investment risk -- reached its widest point in nearly a decade, at more than 2 percent. Analysts said the riots had compounded concerns due to the global economic downturn.

Although violence ebbed this week, on Tuesday about 100 youths attacked a police station, setting fire to a police bus and four cars belonging to officers. For days, protesters have hurled firebombs at police, who responded with teargas.

Shops and cars were smashed and looted in Athens and other cities for days. The National Confederation of Commerce estimates 565 shops were damaged in Athens alone, costing 200 million euros and ruining the Christmas shopping period.

Karamanlis' New Democracy party swept to power in 2004, vowing to clean up politics, but was soon hit by scandals -- from wiretapping to overpriced government bonds sold to state pension funds.

Weekend polls showed overwhelming disapproval of the government's handling of the rioting and it trails the opposition socialists in opinion polls.

The policeman who shot Alexandros Grigoropoulos was charged with murder and jailed pending trial, while his partner was charged as an accomplice.

The killing sparked protests across Europe and IMF head Dominique Strauss-Kahn warned unrest could spread unless the financial sector shared wealth more evenly.