British Prime Minister Theresa May's spokesman urged "calm and restraint" in the Gaza Strip on Monday after deadly clashes ahead of the opening of the US embassy in Jerusalem.
Foreign Office minister Alistair Burt also expressed concern that peaceful protests were being exploited by extremist elements, while adding: "(I) urge restraint in use of live fire."
The prime minister's spokesman said: "We are concerned by the reports of violence and loss of life in Gaza. We urge calm and restraint to avoid actions destructive to peace efforts.
"The prime minister had made her views clear in December that we disagreed with the decision (to move the US embassy). We believe it's unhelpful in terms of prospects for peace in the region."
The spokesman reiterated Britain's commitment to a two-state solution between the Israelis and Palestinian Arabs with Jerusalem as the shared capital.
Violent clashes along the Gaza border left 43 Gazans dead from Israeli fire, and hundreds more wounded, in the conflict's bloodiest day in years.
The clashes erupted before a White House delegation and Israeli officials opened the US embassy at an inauguration ceremony in Jerusalem, and then continued throughout the day.
The organizers of the 'Great March of Return' claim that the purpose of the demonstrations is for Gazans to return to the homes their ancestors may have once lived in within Israel's pre-1967 borders. Hamas stated that after breaching Israel's borders the demonstrators would march on Jerusalem.