Twenty-seven people including 10 Chinese workers held for months by suspected Boko Haram militants have arrived in Cameroon's capital.

The hostages were flown to Yaounde from the country's far northern region after being freed early on Saturday.

They include the wife of Cameroon's Vice-Prime Minister, Amadou Ali.

They were seized in two separate raids in May and July close to the Nigeria border. It is not clear how their release was secured.

Boko Haram is seeking to establish an Islamist state in Nigeria but its fighters often cross the long and porous border with Cameroon.

Many Nigerian civilians in border towns have fled to Cameroon to escape militant attacks, which have been stepped up in recent months.

In July, Cameroon, Nigeria, Chad and Niger agreed to form a 2,800-strong regional force to tackle Boko Haram militants.

Cameroon has reinforced its troops in its northern regions.

The Chinese workers were kidnapped in Cameroon in May

The freed hostages were said to be relieved to be released but weak

The freed hostages were taken to Yaounde general hospital upon their arrival in the capital, Reuters reports.

"You can imagine that after the ordeal they are very happy to be released and very relieved," Issa Tchiroma Bakary, Cameroon's Minister of Communications, told the news agency.

"But they are very weak. They are in very poor physical condition."

President Paul Biya announced their release said in a statement on state radio: "The 27 hostages kidnapped on May 16, 2014, at Waza and on July 27, 2014, at Kolofata were given this night to Cameroonian authorities.

"Ten Chinese, the wife of the Vice Prime Minister Amadou Ali, the Lamido (a local religious leader) of Kolofata, and the members of their families kidnapped with them are safe."

No details were given on the circumstances of the release or whether a ransom was paid.

In July, Cameroon said Mr Ali's wife, Akaoua Babiana, and her maid were abducted in "a savage attack" on his home in Kolofata by Boko Haram militants.

Mr Ali managed to escape to a neighbouring town.

Efforts to step up regional co-operation gained momentum after Boko Haram caused an international outcry by abducting more than 200 girls from a boarding school in north-eastern Nigeria.

The girls are thought to be held in the vast Sambisa forest, along Nigeria's border with Cameroon.