The acting speaker of the lower house of Brazil's Congress has annulled the impeachment process against President Dilma Rousseff and called for a new vote in the chamber.
Waldir Maranhao, who took over as acting speaker last week, said there were procedural flaws in the April 17 vote in the chamber that accepted impeachment charges against Rousseff.
After last month's lower house vote, the impeachment process was passed to the Senate, where a Senate committee recommended that the leftist president be put on trial by the full chamber for breaking budget laws.
In a news release, Maranhao said the impeachment process should be returned by the Senate so that the lower house can vote again.
It remained unclear whether his decision could be overruled by the Supreme Court, the Senate or a majority in the house.
Brazilian markets fell sharply after the surprising decision was announced.
Rousseff, who denies wrongdoing, has been fighting for her political survival for several months as opposition congressmen push aggressively for her to be ousted.
The full Senate had been expected to vote to put Rousseff on trial on Wednesday, which would immediately suspend her for the duration of a trial that could last six months. During that period, Vice President Michel Temer would replace her as acting president.