The UK has expressed its concern over the violence which has taken place in Bahrain, the foreign secretary says.
Security forces in the country dispersed thousands of anti-government protesters at Pearl Square in the centre of the capital, Manama.
William Hague told the Commons he had stressed the need for peaceful action in dealing with the protesters.
At least three people died in the operation, with hundreds more injured.
The Foreign Office is advising British nationals to stay away from protests and avoid all but essential travel around the island.
In Egypt, where calm is returning after President Mubarak agreed to step down last week, the Foreign Office has relaxed its travel advice.
It continues to advise against all but essential travel to Cairo, Alexandria and Suez but has removed Luxor from the list.
In neighbouring Libya the Foreign Office advises people in the city of Benghazi to follow the news on TV and radio and "not to go out in areas where demonstrations may take place".
Mr Hague said he did not believe any UK nationals had been caught up in the violence in Bahrain.
"We have conveyed our concern about these events and the level of violence to the government of Bahrain," Mr Hague said.
'Freedom of expression'
"We are greatly concerned about the deaths that have occurred. I have this morning spoken to the foreign minister of Bahrain and our ambassador spoke last night to the minister of the interior.
"In both cases we stressed the need for peaceful action to address the concerns of protesters, the importance of respect for the right to peaceful protest and for freedom of expression."
It was "essential" that those injured were able to receive immediate medical treatment, he said.
"We urge all sides to avoid violence and the police to exercise restraint and the Bahraini government should move quickly to carry out its commitment to a transparent investigation into earlier deaths and extend this to include today's events and any alleged human rights abuses."
Mr Hague said he had told Bahrain's foreign minister now was the time to build bridges between the island nation's different religious communities.
"I also said we would strongly oppose any interference in the affairs of Bahrain by other nations or any action to inflame sectarian tensions between Bahrain's Sunni and Shia communities," he added.
But Mr Hague said the government did recognise that Bahrain had made important political reforms alongside growing economic success.
"We strongly welcome such steps within the context of the long friendship of Bahrain and the UK under successive governments," he said.
The prime minister's spokesman echoed Mr Hague's comments. "Clearly, we are deeply concerned by the events in Bahrain last night and by the level of violence," the spokesman said.
"We think it is essential that Bahrain now takes further steps on reform that meet the aspirations of its people for greater political and social freedoms."
Shadow foreign secretary Douglas Alexander said UK ministers and officials must ensure Bahrain's government realises the "eyes of the whole world" are watching how the country handles the protests.
The protesters want wide-ranging political reforms and had been camped out since Tuesday. Officials said all chance of talks had been "exhausted".
Clashes earlier in the week left two dead and dozens injured in the country.
The unrest comes amid a wave of protests that has swept through several Arab nations and led to the presidents of Tunisia and Egypt resigning.
Asked about arms exports to Bahrain amid allegations of human rights abuses, Minister for the Middle East and North Africa Alistair Burt said: "We closely consider allegations of human rights abuses.
"We will not authorise any exports which, we assess, might provoke or prolong regional or internal conflicts, which might be used to facilitate internal repression, or which would in any other way be contrary to the criteria.
"In light of events we are today formally reviewing recent licensing decisions for exports to Bahrain. We will urgently revoke licences if we judge that they are no longer in line with the criteria."