WASHINGTON - US Secretary of State John Kerry told a US TV network on Sunday that Washington will “have to negotiate in the end” with Syrian President Bashar al Assad to end the deadly conflict in that country.

Speaking as the war enters its fifth year, Kerry said it was “one of the worst tragedies any of us have seen”.

He said that the international community was upping pressure on Syria’s regime to hold new peace talks, stating “we have to negotiate in the end” with President Assad.

More than 215,000 people are estimated to have been killed in the conflict.

“We are working very hard with other interested parties to see if we can reignite a diplomatic outcome,” Kerry said in an interview with CBS News in the Egyptian resort of Sharm el-Sheikh.

“Everybody agrees there is no military solution; there’s only a political solution,” he said.

Pointedly asked if he is ready to negotiate directly with the Syrian President, Kerry responded that if Assad is “ready to have a serious negotiation” about implementing an agreement made in Geneva in 2012, “people are prepared to do that.”

Kerry omitted the Obama administration’s refrain that Assad will have to relinquish power if there’s to be an end to the conflict that has seen more than 200,000 deaths.

Kerry said negotiations are important “because everybody agrees there is no military solution; there’s only a political solution. But to get the Assad regime to negotiate, we’re going to have to make it clear to him that there is a determination by everybody to seek that political outcome and change his calculation about negotiating. That’s underway right now.”

”We have to negotiate in the end,” said Kerry. “And what we’re pushing for is to get [Assad] to come and do that, and it may require that there be increased pressure on him of various kinds in order to do that. We’ve made it very clear to people that we are looking at increased steps that can help bring about that pressure.”

AFP adds: Amid the dragging stalemate on the ground, Syria has been carved up between government forces, jihadist groups, Kurdish fighters and the remaining non-jihadist rebels.

Diplomacy remains stalled, with two rounds of peace talks achieving no progress and even a proposal for a local ceasefire in the second city Aleppo fizzling out.

After years of insisting Assad’s days were numbered, US Secretary of State John Kerry conceded Washington would have to negotiate with the iron-fisted leader to end the war.

Deputy State Department spokeswoman Marie Harf, however, denied there was any shift in US policy.

“@JohnKerry repeated long-standing policy that we need negotiated process w/regime at table - did not say we wld negotiate directly w/Assad,” she said in a message on her Twitter account.

The conflict began as an anti-government uprising, with protesters taking to the streets on March 15, 2011, inspired by similar revolts in Egypt and Tunisia.

But a fierce government crackdown on the demonstrations prompted a militarisation of the uprising and its descent into today’s brutal multi-front conflict.

The Syrian Observatory for Human Rights said at least 215,518 people had been killed in the past four years, nearly a third of them civilians and including more than 10,000 children.

The full toll is likely to be even higher, because the fate of tens of thousands of missing people remains unknown.

The UN refugee agency UNHCR says Syria is now “the biggest humanitarian emergency of our era.”

Around four million people have fled abroad, with more than a million taking refuge in neighbouring Lebanon, while others are sheltered in Jordan and Turkey - placing a huge strain on those countries.

Inside Syria, more than seven million people have been displaced, and the United Nations says around 60 percent of the population now lives in poverty.

The country’s infrastructure has been decimated, and economists say the economy has been set back by some 30 years.

Despite international outrage at the death toll, and allegations that his regime used chemical weapons against its own people in August 2013, Assad has clung to power.

His forces have consolidated their grip on the capital Damascus, where 18 more people were killed in more regime air raids Sunday and more than 100 injured according to the monitor group.

And Assad’s forces are now moving to encircle rebels in Aleppo to the north.

The assaults have been aided by the government’s increasing reliance on crude barrel bombs, which Assad denies using despite extensive documentation.

Diplomats describe a new willingness to countenance a role for Assad in Syria’s future, although Washington still insists that he has lost all legitimacy and must step down.

“Assad didn’t want to negotiate,” Kerry told CBS television, about the last failed rounds of peace talks in Geneva.

“What we’re pushing for is to get him to come and do that,” he replied when asked if he would negotiate with Assad.

“We are working very hard with other interested parties to see if we can reignite a diplomatic outcome,” Kerry told CBS News.

Kerry’s comments were flashed straight away on Syrian state television.

But international attention has largely shifted away from the war to fighting the Islamic State (IS) group which has captured a large swath of territory in Iraq and Syria, terrorising the population and carrying out horrific beheadings and murders.

Kerry has said Washington’s top priority is defeating IS, and repeatedly blamed Assad for allowing his country to become a magnet for terror groups.