U.S. in fresh push for war on Syria

At a joint press conference Foreign Secretary William Hague said Britain was preparing to "significantly increase" its support for Syria's opposition - and both men urged opposition leaders to meet them.

Mr Hague said he and Mr Kerry would attend a Friends of Syria summit in Rome on Thursday and they both urged the Syrian coalition opposition to go to the meeting.

Syrian Foreign Minister Walid al-Moualem met his Russian counterpart Sergei Lavrov in Moscow today and said Mr Assad was ready to talk with all parties including armed groups.

The rebel Syrian National Coalition has reportedly turned down invitations to Washington and Moscow in protest at what it described as international silence over destruction of the historic city of Aleppo by government missile strikes.

Opposition attacks have also left a bloody trail of civilian casualties.

Yet Mr Hague signalled the growing prospect of military support for rebels following his meeting with Mr Kerry.

"An appalling injustice is being done to the people of Syria which the world cannot ignore," Mr Hague declared.

"We discussed the vital need for a political transition and our firm support for UN envoy Lakhdar Brahimi.

"We agree that for as long as a political solution to the conflict is blocked off the international community has a responsibility to take steps to help prevent the loss of life in Syria.

"We believe we must significantly increase our support for the Syrian opposition on top of our large contributions to the humanitarian relief effort and we are preparing to do just that.

"Our policy cannot remain static as the weeks go by, and it is an important opportunity in Rome on Thursday to discuss this with our allies and partners."

It has been reckoned nearly 70,000 people have been killed in Syria's civil war in the last 22 months since fighting broke out between rebels trying to oust Mr Assad and government forces and allied militias.

Mr Kerry, who succeeded Hillary Clinton and is on an 11-day tour of Europe and the Middle East, said: "The Assad regime has rained down rockets on the people of Aleppo."

He said this "indiscriminate killing of civilians" was unacceptable, adding: "We condemn this in the strongest terms. It is, therefore, evident that Assad has to go."

But Campaign for Nuclear Disarmament leader Kate Hudson said: "As we approach the 10th anniversary of the illegal war on Iraq, Mr Hague should remember the terrible humanitarian consequences of military intervention in that country, and the appalling loss of life which ensued.

"The people of Syria deserve a future of democracy, peace and justice. Western military intervention will not secure that."

Mr Kerry is due to meet Syrian opposition members and Mr Lavrov in Berlin tomorrow.