BUCHAREST (Reuters) - Thousands of Romanians protested in freezing weather across the country on Sunday against attempts by the ruling Social Democrats to overhaul the judiciary, which critics said would threaten the rule of law.

In Bucharest, an estimated 4,000 protesters marched from government headquarters to parliament, where lawmakers will begin debating changes on Monday to the criminal code.

Earlier this month, the Social Democrats used their solid majority to approve a judicial overhaul in the lower house that threatens to put the justice system under political control. The senate is expected to approve the bills next week.

The European Commission, the U.S. State Department, the country’s centrist president and thousands of magistrates have criticized the changes to judicial legislation, saying they could derail the rule of law.

The government denies this is the case.

Outside parliament, the marchers chanted “Thieves’ nest” and “We want justice, not corruption” under sleet and rain. Thousands more protested in the cities of Iasi, Cluj, Timisoara and others.

Attempts by the ruling Social Democrats to change anti-corruption legislation have taken place on and off throughout 2017 in one of the European Union’s most corrupt states.

Romania’s anti-corruption prosecution unit has sent 72 deputies and senators to trial since 2006 alongside cabinet ministers, a sitting Prime Minister and hundreds of mayors and other public officials.

The speakers of parliament’s lower house and senate are both currently on trial in separate cases.