US Secretary of State John Kerry said Monday that the solution to the Syrian conflict must be political not military but that air strikes were essential to stop the Assad regime from killing its own people with chemical weapons.
"Let me be clear, the United States, President Obama, myself, others are in full agreement that the end of the conflict in Syria requires a political solution. There is no military solution, we have no illusions about that," he said after talks with British Foreign Secretary William Hague.
"But a resolution to this has to come about because the parties are prepared to come and negotiate that political solution," Kerry told a news conference at the Foreign Office in London.
"A resolution will not be found on the battlefield, but at that negotiating table. But we have to get to that table."
Hague said that Washington had the "full diplomatic support of the United Kingdom" even though it will not take part in military action.
British lawmakers rejected any involvement in a vote in late August.
"They have the full diplomatic support of the United Kingdom," said Hague.
"The United Kingdom will continue to play an active role in addressing the Syria crisis and working with our closest ally in the coming weeks and months."
Kerry dismissed Syrian President Bashar al-Assad's denials of involvement in a deadly chemical attack on a Damascus suburb on August 21.
The top US diplomat meanwhile said it was necessary to act against "dictators" who kill their own people.
"For almost 100 years, the world has stood together against the use of chemical weapons," Kerry said.
"And we need to hear an appropriate outcry as we think back on those moments of history when large numbers of people have been killed because the world was silent -- the Holocaust, Rwanda, other moments, are lessons for all of us today."