The British embassy in Cairo suspended all public services on Sunday for security reasons, an embassy spokesperson said in a statement.
The embassy declined to give more details due to the sensitive nature of the matter but said it was working with the Egyptian authorities to reopen and resume full service as soon as possible.
“The decision to suspend public services at the embassy has been taken for security reasons and is in the best interests of our staff,” the spokesperson said.
“The decision is independent of our wider travel advice for Egypt.”
It was not clear when the embassy would reopen. The British embassy website said the office of the British Consulate-General in Alexandria was operating as normal.
Egypt has been battling an Islamist insurgency that is largely centered around the Sinai Peninsula, a strategic area near the border with Israel, Gaza and the Suez Canal.
Insurgent attacks have mostly targeted Egyptian police and soldiers, killing hundreds in the past year, but Egypt’s most dangerous militant group recently said it was behind the killing of an American oil engineer in the western desert.
Smaller bombs also regularly explode in Cairo and the Nile Delta, usually causing limited injuries.
The British Foreign Office already advises against all travel to the volatile area of northern Sinai and all but essential travel to most of southern Sinai and to the west of Egypt, particularly near the border with Libya.
“There is considered to be a heightened threat of terrorist attacks globally against UK interests and British nationals from groups or individuals motivated by the conflict in Iraq and Syria. You should be vigilant at this time,” the Foreign Office says on its Egyptian travel advice page.