Protests have taken place across Poland against steps by the new government to neutralise the Constitutional Tribunal as a check on its power, something government opponents are calling a threat to democracy.
During Saturday's protests, participants - with former anti-communist dissidents among them - said they feared for the country's 26-year-old democracy with the government's moves against the court.
The Law and Justice party, which took power last month, controls the houses of parliament as well as the presidency, leaving the constitutional court as the only effective check on its power.
The government of Beata Szydlo, the prime minister, recently appointed five judges to the tribunal.
The ruling party also plans to pass new legislation in the coming week which would essentially make the court unable to work.
A key provision of the law would require a two-thirds majority by the 15-judge tribunal for any ruling to be valid, something almost impossible to achieve on contentious issues.
The result is that the court would not be able to strike down any new legislation that is challenged.
The proposal is expected to pass on Monday.
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A rally in front of the parliament in Warsaw, which drew thousands on Saturday, was disbanded quickly due to an bomb threat which turned out to be a hoax.
Radek Sikorski, former foreign minister and a staunch anti-communist, took part in the gathering in Warsaw, holding up a Polish flag with his family by his side.
There were demonstrations in about 20 other Polish cities as well as in London, Brussels and Tokyo, organisers said.
Last week, Martin Schulz, a German member of the European Parliament, compared the current situation in Poland to a "coup d'etat".