The Foreign Office, which has warned of imminent attacks in the past, has advised against all nonessential travel to the Middle Eastern kingdom since May.
"Following terrorist attacks in Riyadh (search) in May and November, we continue to believe terrorists are planning further attacks in Saudi Arabia and that these could be in the final stages of preparation," the Foreign Office said.
Militants detonated car bombs at Western housing compounds in Riyadh in May, killing 35 people including the nine bombers. Another suicide attack killed 17 people in the capital on Nov. 8.
A Foreign Office spokesman said travel advice was kept under constant review based on assessments of all available information. The spokesman said he could not comment on the nature of the information.