Czech center-right opposition parties have condemned what they call an excessive use of police force against citizens protesting China's human rights record during a recent visit of the Chinese president.

For three days of President Xi Jinping's March visit, police dealt with numerous skirmishes between Czech protesters and what appeared to be well-organized groups of Chinese people supporting their leader.

Police say 23 people were detained in total from both camps.

The opposition Civic Democratic Party and TOP 09 claim police sided with the Chinese and want to know if officers were instructed to do so.

They say Czechs were denied their protest rights, demanding an extra parliamentary session on the issue.

Interior Minister Milan Chovanec denies wrongdoing, acknowledging only one mistake.

Chovanec says an internal police investigation is ongoing.