The speaker read a letter reportedly from Mugabe, in which he said he was resigning immediately and voluntarily in an effort to ensure a "smooth transfer of power," according to the Associated Press. The announcement was met with widespread cheers from lawmakers.
His reported resignation comes amid heightened political tensions in the country.
Mugabe, 93, was placed under house arrest by the military several days ago.
Zimbabwe's military is believed to have taken charge of the country earlier this month.
The first signs of a military takeover emerged Nov. 14 as armored vehicles were deployed near the capital, one week after Mugabe fired his longtime ally Vice President Emmerson Mnangagwa and accused him of scheming to take power, including through witchcraft.
The U.S. Embassy in Zimbabwe issued an advisory that night, urging all employees to stay home the next day and warning American citizens there to shelter in place "as a result of the ongoing political uncertainty."
Zimbabwe's army addressed the country on state-run media on Nov. 15, vehemently denying speculation that it was a coup d'etat and assuring citizens that Mugabe and his family were "safe and sound."
On Nov. 17, Mugabe made his first public appearance since the alleged house arrest. He delivered a speech at a university graduation ceremony in the country's capital, Harare.
His resignation marks a major turning point in Zimbabwe's history. He became the country's first prime minister in 1980 after the end of British colonial rule over the country, formerly known as Rhodesia, in southern Africa. He became president in 1987 and had ruled the country since then.
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