(Adds protest numbers)
By Radu-Sorin Marinas
BUCHAREST, Feb 3 (Reuters) - Romania's ombudsman has challenged in the Constitutional Court a cabinet decree passed earlier in the week decriminalising some graft offences, in an apparent watering down of an anti-corruption drive that sparked mass protests and international condemnation.
The decree would decriminalise abuse-of-power offences in which the sums do not exceed 200,000 lei ($48,000), potentially scuttling an ongoing trial of the governing Social Democrat party chief and benefiting dozens of other public officials.
Tens of thousands took to the streets of Bucharest and 70 other cities and towns across Romania on Friday in the fourth day of nationwide, peaceful protests in which people have demanded an immediate halt to the legislation.
"Repeal it, repeal it," "Corruption kills," read banners carried by demonstrators in Bucharest's main square in front of the government building, many waving the national red, yellow and blue flag.
About 120,000 gathered in Bucharest alone, according to riot police, and overall about 300,000 protested around the country and in several western European capitals.
The government has firmly rejected calls to rescind the decree, though cracks in cabinet unity emerged on Thursday with the resignation of a minister and a call from a vice-president of the ruling party for the measure to be withdrawn.
Ombudsman Victor Ciorbea's move echoed a plea from the Black Sea state's general prosecutor and added to a challenge by the CSM council of magistrates to the top court and by centre-right President Klaus Iohannis.
General Prosecutor Augustin Lazar said on Friday he welcomed the Constitutional Court challenge and that his office had its own case before the Court of Appeals (CA).
Experts say the CA itself could suspend enforcement of the decree as it can rule on the legality of such measures. The decree is due to take effect in a little over one week.
The government adopted the measure in an emergency procedure late on Tuesday, saying this was needed to align ex-Communist Romania with a European Union legal directive to member states that aims "to consolidate some aspects of presumption of innocence and the right to be present at trials".
It has cited a need to ease overcrowding in Romanian prisons as further grounds for the "proposed legislative measures", as the government refers to the decree.
Ciorbea said there was no urgency to the decree as the EU's deadline for compliance with the measure is April next year.
"There would have been plenty of time to discuss such things in a regular, parliamentary procedure, so no one can claim any urgency. The court will now decide whether the decree is constitutional or anti-constitutional," he said.
The decree has triggered some of the biggest nationwide demonstrations since Communist dictator Nicolae Ceausescu was overthrown in an uprising that ended with his death and his wife by firing squad on Christmas Day 1989.
Eight Western powers including Germany and the United States have said they are deeply concerned the decree could undermine Romania's partnerships in the EU and NATO. Romania belongs to both, and hosts a U.S. anti-missile system, but has struggled to combat endemic graft and remains among the poorest EU states.
The Constitutional Court had given the government, parliament and the CSM until Feb. 7 to submit their opinion. -
The government said their legislative changes were also meant to alleviate overcrowding in Romanian prisons.
"As soon as we get all opinions and arguments, on Feb. 7 we will decide a timing for talks," court President Valer Dorneanu told reporters.
"(The court magistrates) will respect the constitution, the laws, our internal rules and our own conscience." (Editing by Mark Heinrich)