South American trade bloc Mercosur suspended Venezuela indefinitely on Saturday, adding to international pressure on President Nicolas Maduro to dismantle a newly created pro-government constituent assembly and restore democracy.

Foreign ministers of Argentina, Paraguay, Uruguay and Brazil announced the decision in Sao Paulo, urging Maduro to release prisoners and immediately start a political transition, Reuters reported.

"We are saying: Stop with this! Enough with the deaths, enough with the repression. It is not possible to inflict such torture on the people," Brazilian Foreign Minister Aloysio Nunes said after the meeting.

Mercosur has no provision for expulsion. It had suspended Venezuela temporarily in December for not complying with the bloc's regulations, and toughened its stance following the controversial election of the constituent assembly on Sunday and the arrest of several opposition leaders