The opposition factions in Ukraine's parliament have called on Prosecutor General Viktor Pshonka to start a criminal investigation into a possible coup attempt.

"The acts of the organizer, who is the president of Ukraine, and the perpetrator, Verkhovna Rada Speaker Volodymyr Rybak, can be qualified under Article 109 of the Penal Code - illegal seizure of power and infringement upon the constitutional system. This article carries a prison sentence of 10 years," Batkivschyna faction leader Arseniy Yatseniuk said at an opposition meeting on Thursday.

The opposition wants the prosecutor general to "open a criminal case into a coup attempt today," he said.

Up to 140 opposition parliamentarians are attending the meeting, which is taking place simultaneously with a session of 244 parliamentary majority members in another building in Kyiv.