London (CNN) -- British Foreign Secretary William Hague met a range of Syrian opposition figures Monday, saying London was "seeking to step up the international pressure on the Assad regime, a regime that has long since lost its legitimacy in the eyes of the wider world."
Syrian President Bashar al-Assad needed to know that "the rest of the world is talking to the Syrian opposition and we are looking for a different future for Syria," Britain's top diplomat said.
"I think the Assad regime will find that more and more governments around the world are willing to work with the opposition," Hague said.
Hague told the opposition leaders that they needed a "unified platform and a unified body," indicating Britain may hope the various Syrian opposition groups could replicate the Libyan National Transitional Council that brought down Moammar Gadhafi.
The Syrians came from two different groups, the Syrian National Council and the National Coordination Body, Hague said.
He met with Syrians including SNC chairman Burhan Ghalioum, Ausama Monajed, Nibras al-Fadel, Haytham Manna, Khalaf Dahowd and Rami Abdel Rahman, a source familiar with the meeting said.
The source asked not to be named because of the sensitivity of the situation.
Syria has faced months of unrest from opponents of al-Assad, and security forces have responded forcefully.
The United Nations says more than 3,500 people have died since the uprising began in March.
The Arab League has demanded that Syria stop the violence.
Syria's government has said it is fighting armed terrorists, maintaining the death toll is much lower than international observers and opposition groups say.