By Luiza Ilie
BUCHAREST (Reuters) - Romania's new leftist government late on Tuesday decriminalized a number of graft offences including some abuse-of-power cases in the ex-communist state's biggest retreat on anti-corruption reforms since it joined the European Union a decade ago.
More than 10,000 people gathered outside government headquarters in the capital, Bucharest, in freezing temperatures and thousands more in cities across Romania shortly after the emergency decree was announced.
Protesters in Bucharest shouted: "Thieves!" and "Traitors!" and called for the government to resign.
Romania's leftists swept into power in December, promising higher wages and pensions in a parliamentary election that underscored a deepening divide between older rural voters, tired of austerity, and younger city-dwellers.
Their plans to ease anti-corruption rules were unveiled earlier this month, triggering the largest street protests since the 1989 fall of communism.
The leftists said the changes were needed to get the criminal code in line with recent constitutional court rulings.
The Cabinet of Prime Minister Sorin Grindeanu has drawn criticism from President Klaus Iohannis, chief judges and prosecutors, civil rights groups, diplomats and the European Commission, which has Romania's justice system under special monitoring.
"Today is a day of mourning for the rule of law," Iohannis said in a statement. "The government has ignored the dreams of millions of Romanians who want to live in a country free of corruption."
Romania is one of Europe's most corrupt states, with graft rife in state administration and many areas of public life. Efforts to stamp out abuse have accelerated over the past four years.
Prosecutors have indicted nearly 2,000 people in cases involving abuse of power that have caused damages totaling up to 1 billion euros in the past three years.
Several leading politicians are under investigation or on trial in abuse-of-power cases, including the leader of the ruling Social Democrats and lower house Speaker Liviu Dragnea.
The emergency decree - which takes effect immediately - would decriminalize some offences, including abuse of power causing financial damage of less than 200,000 lei ($48,000).
It also approved a draft bill granting prison pardons for several offences that now needs parliament's approval.
"This is a strong hit against criminal justice in Romania, and the impact will be major ... on all citizens," anti-corruption legal expert Laura Stefan said about Tuesday's announcement.
(Reporting by Luiza Ilie; Editing by Justyna Pawlak and Peter Cooney)