Three embassies in Venezuela’s capital Caracas have been warned about an imminent firebomb attack, according to diplomats.

There is a “credible” threat to British, American, and Spanish embassies.

The British and US embassies have urged nationals to remain vigilant during the critical period between next Sunday and Tuesday.

An unnamed radical group is believed to be planning the attack.

Meanwhile, British embassies are believed to be more vulnerable to attack by suicide bombers since America beefed-up its security arrangements around key diplomatic outposts.

The Foreign Office said it may have to upgrade security at more than 200 British embassies and missions abroad.

And two consulates in Morocco – in Casablanca and Tangier – will be moved out of the city to unnamed new premises.