Image caption Anti-government protesters have been inspired by uprisings in Egypt and Tunisia

Britons are being warned against all travel to Bahrain after clashes between police and anti-government protesters intensified.

The Foreign Office is also advising UK nationals living in the Gulf state to remain at home.

It urged Bahrain's authorities to avoid the use of excessive force and told all parties to exercise restraint.

Units from the Saudi military have arrived in the country at the invitation of the government.

Bahrain's opposition has said it considers any foreign military intervention to be an occupation and "a conspiracy against the unarmed people of Bahrain".

The latest British government advice upgrades a Foreign Office (FCO) statement issued last month, which warned against all but essential travel.

It said: "The risk of further outbreaks of violence has increased.

"If British nationals do travel within Bahrain, they should maintain a high level of security awareness, particularly in public places and on major highways, and avoid large crowds and demonstrations.

"The airport remains open and transiting through the airport is unaffected by this advice."

Calls for reform

On Sunday, security forces fired tear gas and rubber bullets at demonstrators who had blocked off roads into the financial district of Bahrain's capital Manama.

Clashes were also reported in the city's main square and university in some of the worst unrest for weeks.

Protesters, inspired by the uprisings in Egypt and Tunisia, have called for the reform of the Sunni Muslim monarchy and have threatened to march on the royal palace if their demands are not met.

Earlier this month, the FCO also warned Britons against all travel to the Middle Eastern state of Yemen because of increasing violence.

UK nationals already in Yemen without a pressing need to stay were advised to leave using commercial travel services.