The British embassy in Bangkok has temporarily closed following an upsurge of violence in the Thai capital.
Quinton Quayle, the British Ambassador to Thailand, told the BBC he was in the building and was monitoring the protests taking place nearby.
He advised against all but essential travel to Bangkok and other areas.
Anti-government, red-shirted protesters have been occupying parts of Bangkok since March, and a state of emergency has been called in the capital.
Mr Quayle told the BBC that the embassy was closed to the public as the roads around the building had been blocked off.
He said: "We do have a team here in the embassy, and I'm one of them, who are monitoring the situation, providing advice to the British community, updating our travel advice and generally trying to follow what is a fairly unpredictable and tense situation.
"With outbreaks of violence happening in various parts of Bangkok, it is difficult to keep track of it all."
He advised Britons only to visit the capital if essential and those already there should consider whether they should be travelling around the city.
He said the embassy had been speaking to a number of honorary consuls dotted around the country about the protests but there had been no reports of "serious trouble".
AT THE SCENE
Alastair Leithead, BBC News, Bangkok
The centre of Bangkok is a no-go area. I'm on the main diplomatic street where a lot of the foreign embassies are.
A short time ago, the alarm went off in the park to mark midday and it was eerily quiet, but 10 minutes earlier there was heavy gunfire.
The troops were firing a considerable number of rounds into a park, on the other side of which the protesters have control.
There are areas of confrontation all around the centre of Bangkok. It's heavily militarised. The troops have been firing rubber bullets, tear gas and live rounds.
This road is blocked by a burnt-out bus and by a whole group of red-shirt protesters who have been shooting fireworks at the military.
The whole of this central area is being buzzed by a helicopter. We are hearing reports of someone being killed on the road nearby.
The centre of Bangkok is a very dangerous place to be.
He said that each year up to one million Britons visited the country and the violence was damaging Thailand's reputation.
A Foreign and Commonwealth Office (FCO) spokeswoman told the BBC: "We will continue to monitor developments in Bangkok in order to provide British nationals with the most up-to-date information.
"British nationals in Thailand requiring consular advice should continue to contact our embassy via the hotline which is staffed at all times."
The hotline to the embassy in Thailand is 02 305 8333.
Staff had already been offering a revised service, and the US had closed its embassy in Bangkok.
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