Unrest broke out at Trzech Krzyży Square in the centre of the capital, where police moved back a crowd throwing fireworks toward a church, public broadcaster Polish Radio reported.
The entry to the church was blocked off by a group of nationalists and police, Polish Radio added.
Earlier, demonstrators blocked streets in cities across Poland on Monday in a fresh wave of protests against a ruling on abortion law by the country's top court.
In the capital, protesters caused traffic to grind to a halt on Jerozolimskie Avenue and Marszałkowska street, both busy thoroughfares running through the heart of the city.
State news agency PAP reported that thousands then gathered in front of the Constitutional Tribunal, chanting slogans and brandishing banners reading: "My body, my choice", "The government is not a pregnancy - it can be removed", and "This is war."
It was the fifth straight day of demonstrations against a court ruling which signalled a tightening of Poland’s abortion laws, already among the toughest in the European Union.
The street protests were sparked by a decision on Thursday by the country’s Constitutional Tribunal that abortion of a malformed foetus violates the constitution.