RIO DE JANEIRO — Brazil’s political crisis deepened sharply on Thursday with corruption allegations that threatened to topple the president, undermine reforms aimed at pulling the economy from recession, and leave Latin America’s largest nation rudderless.

Stocks plunged, both chambers of Congress canceled sessions, and the office of President Michel Temer canceled his planned activities in the wake of a Globo newspaper report that he had been recorded endorsing the bribery of a former lawmaker.

Protests were planned in several cities, and opposition politicians took to Twitter and news outlets to call for Temer to resign or be impeached, arguing that his government no longer had legitimacy.

‘‘I can’t see how Temer survives this,’’ said David Fleischer, a political science professor at the University of Brasilia. ‘‘There are just too many people against him now.’’

The country’s main Ibovespa stock index dropped 10 percent within 90 minutes of opening, and trading was stopped for 30 minutes. The Brazilian Real lost 8 percent of its value against the US dollar in the first half of the day.

The scandal deepened as police searched the Rio de Janeiro home and Brasilia office of Senator Aecio Neves.

Neves is being investigated in several corruption cases related to the ‘‘Car Wash’’ probe involving kickbacks to politicians. He has denied wrongdoing.

Late Wednesday, Globo reported that Neves had been recorded asking JBS meat-packing company executive Joesley Batista for $700,000 to pay for his ‘‘Car Wash’’ defense. On Thursday, the Supreme Federal Tribunal, the country’s highest court, suspended Neves from office indefinitely.

Globo also reported that Batista had recorded Temer endorsing a bribe to silence former speaker of the House Eduardo Cunha. In a statement late Wednesday, the president’s office denied the allegation.

Associated Press