Nigerian police are working to rescue seven children and a man who were abducted from an orphanage in the capital over the weekend.

The children and a staff member of the Rachel's Orphanage Home in the capital city, Abuja, were abducted Saturday by a large group of armed men who broke into the home.

"We have launched a strategic operation to ensure they are safely rescued," police spokeswoman Mariam Yusuf, told the Associated Press Monday.

"The abducted children are vulnerable people," the founder of the orphanage, Rachel Alajeshe, told The Associated Press. The children are aged between 10 and 13 and are girls and boys, she said.

Kidnapping is a major problem in the West African country. Gunmen have carried out mass abductions of children either for political reasons or to demand ransom.

The most serious abduction occurred in April 2014 when members of the Jihadist group Boko Haram abducted 276 girls from the Government Secondary School in Chibok in Nigeria's northern Borno State.

Boko Haram said at the time that it abducted the girls as part of its campaign to stop girls from attending schools. About 100 of the girls are still missing.

Last month, armed men abducted more than 300 students from the Government Science Secondary School in Kankara, a boys boarding school in Katsina State.

The children were freed about a week later amid speculation that ransom was paid to secure their release. The government denies any money was paid.

The high incidence of kidnapping in Nigeria highlights the country's insecurity. Boko Haram and its breakaway faction, the Islamic State West Africa Province, and numerous armed groups are blamed for the insecurity in the country.