Cameroon's government announced that 27 hostages presumed to have been kidnapped by Boko Haram, including 10 Chinese construction workers and the wife of a vice prime minister, have been freed.

The hostages were returned early on Saturday morning and "are safe and sound,'' according to a statement from President Paul Biya's office read on state radio, the Associated Press news agency reported.

The Chinese road construction workers were kidnapped in May from their base in Waza, in Cameroon's Far North region.

Francoise Agnes Moukouri, wife of vice prime minister Amadou Ali, was among a group of 17 people kidnapped in a July attack targeting their residence in the border town of Kolofata. Officials said at the time that 200 fighters stormed the residence, though Ali himself was away.

As the fighters retreated with their hostages, they set fire to the residence, stole safes and vehicles and killed at least five people, a military spokesman said at the time.

A local religious leader was also abducted in the July attack and released Saturday, according to the Cameroon government statement.

Boko Haram never claimed responsibility for the kidnappings, but both incidents raised concerns that the Nigeria-based rebels were expanding their operations in Cameroon as the government became increasingly involved in regional efforts to contain them.

Cameroon says it does not pay ransoms in kidnapping cases, and Saturday's brief statement provided no details on the conditions of the hostages' release.

Government spokesman Issa Tchiroma Bakary said he could provide no details. On Friday he claimed to have no knowledge of ongoing negotiations.

On Wednesday, however, witnesses said Ferdinand Ngoh Ngoh, the secretary-general of Cameroon's presidency, arrived in Maroua, the capital of the Far North region, fueling speculation that negotiations were reaching a conclusion.

Ngoh Ngoh was credited with sealing the release of other high-profile hostages, including a French priest kidnapped last November and freed the following month.