Story highlights ISIS used the former palace as a training center for foreign recruits, UK officials say

Mosul is the largest city remaining under the terror group's control

(CNN) British fighter jets have struck an ISIS training complex in one of toppled Iraqi dictator Saddam Hussein's former palaces in Mosul, the UK's Ministry of Defense said Wednesday.

Two Royal Air Force Typhoons carried out the strikes Monday on one of the terror group's strongholds in Mosul as part of a targeted coalition attack, the ministry said in a statement.

Extensive surveillance showed the palace, close to the Tigris River, contained a training center for foreign recruits and offices dedicated to internal security in the group's so-called caliphate.

The jets were armed with the RAF's largest guided bombs, the Enhanced Paveway III , and first struck the headquarters, then the security center. Initial indications were that the mission was successful.

"Daesh has been losing followers and territory for months, and emphatic strikes like this show that we and the coalition will not waver," UK Defense Secretary Michael Fallon said, using an alternative name for ISIS.

Read More