Vojtěch Filip has been re-elected chairman of the Communist Party.
He was elected in a second-round secret ballot, narrowly defeating "orthodox wing" head Josef Skála. Mr Filip is himself regarded as a more hardline leader than some in the party.
In the ballot he received 165 votes and his challenger 145. The congress is taking place behind closed doors following an address by the president earlier on Saturday.
President Miloš Zeman reminded delegates of the Communist Party at their convention in Nymburk, east of Prague on Saturday that so-called Victorious February (Vítězný únor, when the Communists seized power in Czechoslovakia in 1948) was anything but and had led to totalitarian rule.
He recalled democrats such as Milada Horáková or General Helidor Píka who were murdered by the regime, saying those had not been "mistakes or deformations" of the system "but crimes". In his speech he said he wished he could with a clear conscience call the Communists "a democratic party" and appealed to delegates to exercise greater self-reflection moving forward.
Mr Zeman is the first post-1989 president to attend a Communist Party convention.
For the first time since 1989, the Communists hold important cards when it comes to the formation of the next government: the president warned the Communist Party not to make exaggerated demands and not to miss the opportunity at hand.
The election-winners ANO and the Social Democrats are currently negotiating a minority government which will effectively require their support in most key votes including a vote of confidence in the lower house.
The police had to step in to prevent a number of demonstrators in Nymburk from crashing the Communist Party congress after the departure of President Miloš Zeman on Saturday. Members of the force as well a on-site anti-conflict team stopped demonstrators on the stairs of the local town hall and persuaded them to turn back.
The demonstration in front of the town hall is continuing as planned and has been attended by several hundred people including public figures such as first-round presidential candidate Michal Horáček and TOP 09 senator Tomáš Czernin. Protestors have expressed opposition to the Communist Party being legitimized, as they see it, by the current head of state as well as politicians seeking to form a minority government.
Church representatives and hundreds of believers met at Prague's St. Vitus Cathedral on Saturday to welcome the return of Cardinal Josef Beran's remains at the end their journey from St. Peter's Basilica. The cardinal, whose name came to symbolize opposition to totalitarian regimes, died in Rome in 1969. His last wish was for his remains to one day be returned to his homeland.
The cardinal's coffin arrived in Prague on Friday evening by military plane and was greeted by a special delegation.
Church bells were rung across the Czech capital to mark the historic occasion.
On Saturday, the coffin was transported to St. Vitus Cathedral at Prague Castle by a horse-drawn open carriage. Cardinal Dominik Duka welcomed the return of his predecessor in a mass dedicated to Saint Vojtěch.
Over the next three days, the coffin will remain on display for anyone to come and kneel before to pay their respects.
This Saturday, April 21, was the warmest day of the year so far in the Czech Republic with the temperature hitting 29 degrees Celsius in places. Meteorologists reported that records for the day had been broken at some 100 of 147 measuring stations. Many Czechs took the opportunity to spend at least part of the day outdoors.
The Czech women's tennis team is a win away from securing the final in the Fed Cup in November, leading 2:0 against Germany. The Czechs got wins from Petra Kvitová who defeated Julia Görges and Karolína Plíšková who defeated Angelique Kerber in straight sets.
Partly cloudy conditions are expected on Sunday with some sunny periods. Daytime highs should reach temperatures of around 23 degrees Celsius.