Foreign Secretary William Hague has said he is "deeply concerned" by the "unacceptable violence" used against protesters in Libya, Bahrain and Yemen.
In a statement, Mr Hague condemned the violence in Libya, saying reports of the use of heavy weapons fire and a unit of snipers were "horrifying".
He called on the government to stop using force and rein back the army.
Mr Hague also spoke to Bahrain's crown prince, expressing disapproval of live ammunition use on protesters there.
The foreign secretary has urged the Bahraini authorities to hold to account those responsible for deaths of protesters in Bahrain.
Mr Hague said: "Governments must respond to legitimate aspirations of their people rather than resort to the use of force, and must respect the right to peaceful protest."
Media access 'restricted'
He said he had received reports that 35 bodies were brought to one hospital alone during the violence in Libya and media access had been "severely restricted".
"I call on the authorities to stop using force and to rein back the army in confronting the demonstrators.
"The absence of TV cameras does not mean the attention of the world should not be focused on the actions of the Libyan government," he said.
He went on to say he was "deeply concerned" by reports of the harassment of journalists in Bahrain.
"I urge the Bahraini authorities to reach out to the protesters and to hold to account those responsible for deaths," he said.
Referring to the content of a telephone conversation he had with the Gulf state's crown prince, the foreign secretary said he had "expressed the UK's deep concern about the situation and strong disapproval of the use of live ammunition against protesters".
He said: "I reiterated the need for an end to the use of force against peaceful protesters.
"I strongly supported the crown prince's efforts to initiate a national dialogue. The UK calls on all concerned to respond to this offer."
At least 50 people were wounded in Bahrain on Friday as the army fired on protesters following the funerals for four demonstrators killed when troops cleared Pearl Square early on Thursday.
In Libya, the number of people killed in three days of protests has risen to 84, according to the New York-based group Human Rights Watch.
The main focus of the demonstrations against Col Muammar Gaddafi's 42-year rule has been the second city Benghazi, where security forces are said to have attacked protesters again on Saturday.
At least five people have been killed during widespread anti-government demonstrations in Yemen.
Earlier, the former foreign secretary Sir Malcolm Rifkind - who now chairs the Commons intelligence and security committee - told the BBC Radio 4's Today programme the protests across the Middle East resembled events in eastern Europe in 1989.
"Although the problem in Eastern Europe ultimately was Soviet control, that had led to a lack of legitimacy in the eyes of their own people, the people who lived in Poland, Hungary and these other countries.
"The same problem now exists in the Middle East. These governments - these regimes that have existed for 20, 30, sometimes 40 years in the case of Gadaffi - they've lost legitimacy. And once that happens, then the habit of loyalty disappears with it," he said.
Britons have been advised against all but essential travel to Bahrain and non-essential travel to certain areas of Libya.
The UK has revoked several arms export licences to Bahrain following concern over the suppression of demonstrations.