A trove of testimonies from more than 200 people who accuse senior Ugandan officials, including the president and his son, of torture, killings and other crimes against humanity has been submitted to the International Criminal Court in The Hague, a lawyer for the complainants said on Tuesday.

The filing is an effort to bring international scrutiny to what human rights observers have called a brutal government crackdown on opposition groups and activists in the East African nation in the months before and after the country’s bloody 2021 elections.

The briefing accuses nine top Ugandan officials of abuses, including President Yoweri Museveni, who has ruled the country with an iron grip for almost four decades, and his son, Gen. Muhoozi Kainerugaba, who has been maneuvering to succeed his father.

A total of 26 officials are accused of aiding and abetting the incarceration and systematic abuse of Ugandans, particularly supporters of the musician turned opposition leader Bobi Wine, who ran for president in 2021.

The president’s deputy press secretary, Faruk Kirunda, called the accusers political opponents who were “peddling wrong information” and running to the international court “with the aim of tarnishing the image of President Museveni.”

Andrew Mwenda, a spokesman for the president’s son, said in a text message: “Were they tortured? YES! Who directed it? We need to find out. It makes sense for them to accuse a son of the president since it increases the profile of their case.”

It can take months, or even years, for the International Criminal Court, or I.C.C., to announce whether it will investigate a case. Karim Khan, the court’s chief prosecutor, previously said that his office is short on staff and budget, and overwhelmed with investigations, including allegations of war crimes in Ukraine and Afghanistan.

The prosecutor may be reluctant to investigate the Uganda allegations, some analysts said. The court has been heavily criticized for prosecuting the majority of its cases in African countries, even though some were opened at the request of African governments.

The filing was shown to The New York Times by Bruce I. Afran, a lawyer based in Princeton, N.J., whose team gathered the testimonies. He also represents several leading opposition figures in Uganda.

In the documents, activists, opposition leaders and government critics described being waterboarded, whipped and stabbed, having chemicals thrown at them or being forced to lie down next to corpses.

The filing accuses Mr. Museveni of bearing direct responsibility for the torture because he is the commander of the armed forces.

The accusations could intensify criticism of Mr. Museveni’s government, which recently passed a sweeping anti-gay law that rights groups consider among the most punitive in the world.

An I.C.C. investigation could also complicate the politics of succession in Uganda ahead of the 2026 elections. General Kainerugaba, 49, has made it clear he wants to replace his 78-year-old father. But he has irked the older man with provocative tweets, including floating the idea of invading Kenya.

Uganda has been a party to the Rome Statute that established the I.C.C. since 2002 — even though Mr. Museveni has criticized the court and threatened to pull out.

Tom Maliti, a researcher who has monitored cases at the I.C.C., said, “The prosecutor’s office is highly aware of the criticism that they have been focusing on Africa.”

The court’s cases against government officials in Africa have not been successful, he noted, adding that any prosecution would have to rely on the cooperation of the Ugandan government to collect evidence and interview potential witnesses.

Most of those providing testimony are anonymous because many are still in Uganda, Mr. Afran said. But several others, who sought asylum in Europe or the United States, are named. They include Kakwenza Rukirabashaija, a prominent writer, and Amos Katumba, the founder of a nongovernmental organization who has partnered with Mr. Wine on projects.

Many testified that security forces had broken into their homes and arrested them, or whisked them away on the street into unmarked vans. They said they were beaten, burned with hot irons, electrocuted, made to eat feces, forced to drink urine or had their teeth removed.

Mr. Museveni has acknowledged that hundreds of what he called “terrorists” and “lawbreakers” had been arrested during the election season, and that an elite commando unit led at the time by his son had “killed a few.”

Four victims say in the briefing that the president’s son visited them in the detention centers where they were tortured. One is Mr. Rukirabashaija, the author of a book satirizing the president, who was arrested in 2021 after mocking the president’s son on social media.

Mr. Rukirabashaija told The Times last year that he had been whipped and his thighs plucked with pliers in prison, where General Kainerugaba visited him three times. On Tuesday, the general’s spokesman denied the two had ever met.

When he was released last year, Mr. Rukirabashaija fled the country and now lives in Germany.

“The rule of law in Uganda does not function because the courts are subservient to the government,” he said in a phone interview on Tuesday. “I hope we can now find justice.”

Marlise Simons contributed reporting from Breval, France.