7:06 p.m. Opposition and separatist MPs, along with the Speaker, Carme Forcadell, have now returned to the chamber.
The session in the Catalan Parliament at which First Minister Carles Puigdemont is expected to declare some kind of independence from Spain was suddenly delayed minutes after it was due to have begun.
TV3 reported the delay was at Mr. Puigdemont's request.
Opposition group MPs had already entered the chamber. Separatist MPs and the Speaker, Carme Forcadell, had not.
Jean Claude Juncker's Deputy Chief Spokeswoman, Mina Andreeva, denied on Twitter that he was in last minute urgent talks with Puigdemont.
El País, El Independiente and La Vanguardia reported the delay was related to discrepancies with the CUP, the radical-left party that supports the governing coalition, because the text of Mr. Puigdemont's speech did not mention independence directly.
The Popular Party (PP) and Ciudadanos also petitioned the Speaker to cancel the session.
The CUP tweeted that the PP and Ciudadanos wanted to filibuster the session: "Not one step backwards. Today we proclaim the Republic. #NoFear #WeWillWin".