Following talks with British Foreign Secretary Philip Hammond, U.S. Secretary of State John Kerry said in London that Syrian President Bashar Assad must leave office. He was willing to negotiate the timing for such a move.

Kerry also sought help from Russia and Iran on the issue.

"We need to get to the negotiation. That is what we're looking for and we hope Russia and Iran, and any other countries with influence, will help to bring about that, because that's what is preventing this crisis from ending. We're prepared to negotiate. Is Assad prepared to negotiate, really negotiate? Is Russia prepared to bring him to the table?" said Kerry, according to The Times of Israel.

Russia's recent military support of Syria has the U.S. worried. U.S. officials say that heavy Russian equipment, including tanks, helicopters and naval infantry forces, have been moved to Latakia. Russia appears to be getting involved in order to complicate America's air campaign against Islamic State targets in Syria while preventing Assad suffering any more defeats.

"For the last year and a half we have said Assad has to go, but how long and what the modality is ...that's a decision that has to be made in the context of the Geneva process and negotiation. It doesn't have to be on day one or month one ... there is a process by which all the parties have to come together and reach an understanding of how this can best be achieved," Kerry said, according to News Max.

According to the UN, the ongoing Syrian conflict which began over four years ago has seen more than 200,000 Syrians killed, more than four million seeking refuge abroad and about seven million being internally displaced.

Speaking on Assad's removals, Kerry said that he did not have a specific time frame and it "doesn't have to be on day one or month one or whatever. I just know that the people of Syria have already spoken with their feet. They are leaving Syria," reports The Christian Science Monitor.