LONDON — Days after the deadly hostage crisis in Algeria, Britain, Germany and the Netherlands on Thursday warned of an imminent threat to Westerners in neighboring Libya and urged their citizens to leave the eastern city of Benghazi.

Both Germany and Britain exhorted any of their citizens who may still be in Benghazi to leave immediately. A spokesman for the Dutch Foreign Ministry quoted by The Associated Press said “staying in this area is not to be advised.”