British travellers are being urged to leave Yemen as soon as possibly as vast opposing crowds gather on the streets of capital Sana’a.

As many as 10,000 people have gathered to demonstrate against the rule of president Ali Abdullah Saleh, while a similar number have gathered in support.

The developments follow the deaths of up to 50 demonstrators in previous confrontations.

Fast moving events have prompted the Foreign Office to urge British nationals to leave Yemen by commercial means.

“A rapid deterioration in the security situation is possible if negotiations between the President and the opposition breakdown,” warned the Foreign Office.

“Routes in and out of Sana’a and the other major cities may be blocked and airports closed or inaccessible.”

Yemenia, British Airways, Gulf Air, Egypt Air, Saudi Arabian Airlines, Qatar Airways, Emirates, Turkish Airlines, Felix Airways, Royal Jordanian and Kuwait Airways all offer services out of Yemen.

Contact details for each can be found here.

“It will be very difficult for the British Government to provide consular assistance in the event of a further breakdown of law and order and increased violent civil disorder,” continued the FCO.

“British Embassy staff numbers in Sana’a are being temporarily drawn down to a small core team with immediate effect. 

“This will further affect our ability to offer consular assistance, including help with evacuation.”

In a speech to his supporters, the president - who has been in office for more than three decades – pledged to relinquish power, but only to “safe hands”.