Ansar Beit al-Maqdis has claimed responsibility for an attack on a tourist bus on Sunday.
The Egyptian government has told the BBC that it is taking seriously an alleged 48-hour ultimatum by Islamist militant group Ansar Beit al-Maqdis calling on all tourists to leave Egypt.
The threat was reportedly made on a private twitter account “affiliated with” the group, according to Reuters.
The group has denied having any social media accounts, but Reuters claims the account has been accurate in the past.
The Egypt government has struggled against rising militancy in the Sinai.
A spokeswoman at the Egyptian embassy in London said that while the government could not be sure of the authenticity of the threat, “extra precautions have been taken in recent days to protect tourists in the resort area of Sharm El Sheikh”.
The group earlier claimed in an official statement that it was responsible for a deadly attack on a tourist bus on Sunday.
Three South Koreans and an Egyptian were killed in the attack.
The al-Qaeda-inspired militant organisation, whose name means “Champions of Jerusalem”, has increasingly turned its attacks against the Egyptian police and army.
The Sinai peninsula has become increasingly lawless since President Hosni Mubarak was overthrown in 2011.
Militants further stepped up their attacks after President Mohamed Morsi was ousted by the army last year.