Abuja says its embassy in Guinea-Bissau is offering protection to Fernando Dias after "imminent threats" to his life

Nigeria has granted asylum to Guinea-Bissau opposition figure Fernando Dias da Costa, after a disputed election triggered a military takeover in the West African country, the authorities have said.

The Nigerian Foreign Ministry on Monday said its embassy in Bissau offered protection to Dias after "imminent threats" to his life were reported following the November 23 vote and subsequent coup that ousted Bissau-Guinean President Umaro Sissoco Embalo.

The ministry also requested the West African regional bloc ECOWAS to deploy its troops to Guinea-Bissau to protect Dias.

The move comes as mediators from ECOWAS, led by Sierra Leonean President Julius Maada Bio, held talks with the new military leadership to press for a return to constitutional order.

Dias was Embalo's main challenger in the presidential poll, held alongside legislative elections. Both men claimed victory before official results were due amid complaints about the exclusion of key opposition leader Domingos Simoes Pereira and his party from the ballot, which critics said had undermined the credibility of the process.

READ MORE: Guinea-Bissau president flees after post-election coup

Three days after voting, soldiers seized power, suspended the electoral process, closed borders and media outlets, and installed a High Military Command to run the country. They said they had intervened against a criminal plot involving senior officials and foreign actors, and later named army chief General Horta Inta-a as transitional leader for one year.

Dias has claimed he won the election outright in the first round and reportedly accused Embalo of using the military to block the announcement of results, calling the events a "staged" or "ceremonial" coup.

Embalo, who was briefly detained by soldiers, has since left Guinea-Bissau. Senegal's government confirmed he was flown to its territory last week, while some reports say he later traveled on to Brazzaville in the Republic of Congo.

The African Union and ECOWAS have condemned the coup, suspended Guinea-Bissau from regional decision-making bodies and demanded the release of detainees, the publication of full election results, and a swift return to constitutional order.

Last week, ECOWAS said it reserved the right to use "all options" within its laws, including sanctions on entities deemed culpable of disrupting the electoral and democratic process in Guinea-Bissau.