A Japanese oil research group might evacuate 15 staff from Saudi Arabia due to rising concerns over terrorist attacks in the kingdom and other oil-producing nations in the Middle East, an official said Tuesday.

The government-backed Japan Cooperation Center, Petroleum has started talks with Saudi Arabian Oil Co., or Aramco, to determine whether to evacuate the researchers. The researchers are taking part in a joint project with Aramco.

The move follows a weekend attack at a housing compound in Saudi Arabia that killed 22 people, mostly foreign oil industry workers. Eleven of the researchers reside at the Kohbar compound where the attack took place and four others live near it.