HARARE, Zimbabwe — Zimbabwe’s military said early Wednesday that it had taken custody of President Robert Mugabe, the world’s oldest head of state and one of Africa’s longest-serving leaders, in what increasingly appeared to be a military takeover in the southern African nation.
After apparently seizing the state broadcaster, ZBC, two uniformed officers said in a short predawn announcement that “the situation in our country has moved to another level.” While denying that the military had seized power, they said that Mr. Mugabe and his family “are safe and sound, and their security is guaranteed.”
“We are only targeting criminals around him who are committing crimes that are causing social and economic suffering in the country in order to bring them to justice,” said the main speaker, who was identified as Maj. Gen. S. B. Moyo, the army’s chief of staff.
General Moyo — who was not widely known to the public but who was considered close to the commander of the Zimbabwe Defense Forces, Gen. Constantine Chiwenga — warned that “any provocation will be met with an appropriate response.”
Around 6 a.m. on Wednesday, taxis were running on the main roads leading to central Harare and people seemed to be making their way to work. Some soldiers could be seen on the main roads but were not stopping commuters.
After the short announcement, commercials on farming and corn seeds appeared on the state broadcaster. There was no further clarification of the whereabouts or status of Mr. Mugabe, 93, who is the only leader his nation has known since independence in 1980.
Asked in a brief telephone interview about reports of a possible coup, the country’s information minister, Simon Khaya Moyo, said, “What can I say? I don’t know about that.” He did not elaborate.
The television announcement came after a long night of rumors and sketchy reports in Harare that a coup might be underway. The day before, in a remarkable act of defiance, General Chiwenga, had warned that “when it comes to matters of protecting our revolution, the military will not hesitate to step in.”
General Chiwenga was considered close to Vice President Emmerson Mnangagwa, whom Mr. Mugabe summarily expelled from the government and the governing ZANU-PF party last week. The move was widely seen as clearing the path for Mr. Mugabe’s wife, Grace, 52, who had been amassing growing political power in the past two years as her aging husband’s health declined visibly.
Since his removal, the whereabouts of Mr. Mnangagwa, who like Mr. Mugabe was a veteran of the country’s struggle for independence, has been shrouded in mystery.
The question of who will succeed Mr. Mugabe has long haunted Zimbabwe and its political class and led to conflicts among its members even as the country’s once-promising economy shriveled.
In Harare, as uncertainty over the political situation grew overnight, foreign embassies warned their citizens to stay indoors on Wednesday. The United States Embassy said on its website that “as a result of the ongoing political uncertainty through the night, the ambassador has instructed all employees to remain home tomorrow.”
American citizens, the embassy said, “are encouraged to shelter in place until further notice.”
On Tuesday, neither the military nor Mr. Mugabe issued any public statements even as rumors of a possible coup surfaced on social media and in the streets. But Mr. Moyo asserted in a statement that “the ruling ZANU-PF reaffirms the primacy of politics over the gun.”
Mr. Moyo, who is also the party’s national secretary for information and publicity, said the statement by General Chiwenga “suggests treasonable conduct on his part as this was meant to incite insurrection and violent challenge to constitutional order.”
“Purporting to speak on behalf of the Zimbabwe Defense Forces,” he said, “was not only surprising but was an outrageous vitiation of professional soldiership and his wartime record as high-ranking freedom fighter, entrusted with command responsibilities in a free and democratic Zimbabwe.”
Mr. Moyo’s statement, broadcast during the evening news hour on state television, came hours after a leader of the party’s Youth League made similar remarks at the ZANU-PF headquarters in Harare.
Kudzanayi Chipanga, the youth league’s secretary, suggested that military officers unhappy with the government should first return to civilian life if they wanted to become politicians.
“General Chiwenga and all those in the security sector who wish to engage in politics are free to throw their hats in the ring and not hide behind the barrel of the gun,” said Mr. Chipanga, who became a favorite of Zimbabwe’s first family after he helped organize a march last year in support of Mr. Mugabe’s leadership.
The youth league accused the general of siding with a faction loyal to Mr. Mnangagwa. The league has urged that Mrs. Mugabe be endorsed as the new vice president in a party conference scheduled for next month.