Venezuela's opposition-led parliament has voted to open a trial against President Nicolas Maduro, accusing him of violating the constitution.
The move comes after last week's suspension of a referendum process seeking to remove Mr Maduro.
The government said the vote was meaningless, referring to an earlier court ruling that had declared parliament illegitimate.
President Maduro later accused MPs of attempting to stage a "coup".
He said a meeting of the country's defence council would be held on Wednesday.
The further rise in tensions comes despite the fact that on Monday both the government and the opposition agreed to hold crisis talks.
Mass protests planned
During Tuesday's session, MPs also voted for President Maduro to appear before parliament in a week's time.
"We will show clearly to Venezuela and the world that in this crisis, responsibility for breaking the constitution has clearly been Nicolas Maduro's," parliament majority leader Julio Borges said.
Reacting to the vote, Vice-President Aristobulo Isturiz said that "legally, the National Assembly does not exist".
He was referring to the Supreme Court's ruling that parliamentary resolutions were null and void until the removal of three MPs linked to vote-buying accusations.
The parliament's trial of Mr Maduro is unlikely to result in any sort of action against him, the BBC's Will Grant in Central America reports.
The country's military top brass also delivered an address on national television supporting the Socialist government. The army said it was watching the political situation carefully.
Mr Maduro, a former bus driver and union leader, is blamed by the opposition for Venezuela's dire economic situation. The oil-rich country is facing widespread food shortages and spiralling inflation.
The opposition is trying to hold a recall referendum that would allow Mr Maduro to be removed from office - but electoral authorities suspended the process last week.
The official reason was allegations of fraud during the gathering of signatures for the first petition required to enable the referendum.
However, opposition lawmakers have long accused the National Electoral Council of being under the government's control.
In an emergency parliamentary session on Sunday, MPs approved a resolution accusing Mr Maduro's government of engaging in "an ongoing coup d'etat".
The Organization of American States (OAS) also said it was "profoundly worried" by the electoral authorities' decision.
Hundreds of students protested on Monday in San Cristobal, a city near the Colombian border. Nationwide protests are planned for Wednesday.
Mr Maduro has accused the opposition of having links to foreign states, the US in particular, and of seeking to overthrow him to "lay their hands on Venezuela's oil riches".