Administrative authorities in Cameroon say they are tracking armed terrorists who this week killed a Kenyan missionary in the town of Eyumojock in the restive southwest region of the central African state.

The slaying happened as many missionaries and foreign workers have been leaving the area following other attacks, and as the government of Cameroon and foreign embassies in that country have urged those workers to leave.

Nigerians living in Cameroon's political capital Yaounde sing in a special ceremony Wednesday to welcome seven fellow citizens who fled fighting in the towns of Kumba and Kumbo in the restive English-speaking northwest and southwest regions.

Among them are Okafor Stanley, his wife Okafor Emmaculate Ngozi  and their one-year-old baby. Okafor Emmaculate Ngozi says she fled from Kumbo in the northwest after she and her husband were kidnapped by armed men and tortured until they paid a $6,000 ransom last week.

"You need to have seen these guys, the way that they are dressed, the way that they are dirty, the way that they are masked," said Ngozi.

"The way that they talk. They were seven in number, all of them were having guns. They took us to an unknown destination, I can not tell you where we were taken. In short I can not describe them because it was a very bitter experience."

The couple left their hometown Onitsha and settled in Kumbo three years ago. They abandoned everything and trekked over 40 kilometers before a car transported them to Yaounde where the Nigerian community took them in.

They are among an unknown number of foreign nationals who have fled the English-speaking regions after attacks, arson, kidnappings and killings.

In April, authorities in Cameroon said they freed 18 people, including 12 European tourists, who were seized by separatists in the English-speaking regions.

Several embassies now caution workers against travelling to the violence-hit areas.

Cameroon's territorial administration minister, Paul Atanga Nji, says although security has been increased, the country still needs the collaboration of every citizen for those who have fled to return when returns to normal live.

Unrest in Cameroon's northwest and southwest regions began in 2016, when English-speaking teachers and lawyers staged demonstrations criticizing what they called the marginalization of the Anglophone population, which accounts for about one-fifth of the country's 25 million people.

The government says over 1,200 civilians, military troops and armed separatists have been killed.