Nigeria‘s state security agency said on Wednesday it had thwarted plans by Boko Haram militants linked to Islamic State to attack the British and United States embassies in the capital Abuja.

The Department of State Services (DSS) said it arrested five suspected members of the Islamist militant group based in Benue state, in the country’s middle belt, between March 25 and 26.

“The group had perfected plans to attack the UK and American Embassies and other western interests in Abuja,” it said in an emailed statement.

The security service said another suspected Boko Haram member, arrested on March 22, in northeastern Yobe state, confessed details of the plot. The British High Commission and U.S. embassy in Abuja did not immediately respond to a request for comment.

Boko Haram has killed more than 20,000 people and forced more than 2 million to flee their homes since 2009 in an insurgency aimed at creating an Islamic state in the northeast of Africa’s most populous nation.

Attacks have also crossed into neighbouring Cameroon and Niger.