U.S. Secretary of State John Kerry said on Sunday that attempts to find a solution to the Syrian conflict may have to involve negotiations with President Bashar Assad's government if a peaceful political transition is to be achieved. Sunday was the fifth anniversary of the conflict, which has left over 200,000 people dead.

Speaking in an interview on CBS News, Kerry said that the United States is engaged in talks with allies to put pressure on Assad to end the conflict. “We have to negotiate in the end...We've always been willing to negotiate in the context of the Geneva I process," he said, referring to a 2012 plan to end the crisis.

However, State Department spokesperson Marie Harf later told Reuters that Kerry was not specifically referring to Assad, and stressed Washington’s standing policy to never negotiate with the Syrian leader. "By necessity, there has always been a need for representatives of the Assad regime to be a part of this process. It has never been and would not be Assad who would negotiate - and the Secretary was not saying that today.”

In 2012, a group of nations led by the U.N. held a round of talks that called for ending the conflict by forming a transitional government and holding democratic elections in Syria. Another round of talks, in 2014, with representatives from the Syrian government and rebels collapsed without any tangible result. During those talks, Kerry stressed that Assad had no place in Syria’s political future.

"Bashar Assad will not be part of that transition government. There is no way — no way possible in the imagination — that the man who has led the brutal response to his own people could regain the legitimacy to govern," he said in 2014.

Another round of talks, hosted by Russia in January, was boycotted by the Syrian National Coalition (SNC), a leading opposition alliance that Western governments have backed. The talks ended with nothing but an agreement to hold further talks at an undecided time. Kerry also blamed Assad’s lack of interest in negotiations for the Geneva summit’s failure. "Assad didn't want to negotiate. What we're pushing for is to get him to come and do that."

On Sunday, the SNC also stressed that Assad stepping down would be a key requirement of any agreement it would accept. “The overthrow of the head of the regime and its security apparatus is a key demand of the revolution as part of any future political solution and is also a primary goal of any negotiation process,” the group said in a statement on Twitter, according to Reuters.

President Barack Obama has maintained that “the time has come for Assad to step aside,” since 2011, when the Syrian leader first began his alleged campaign of killing peaceful protesters.

In 2012, Obama announced he had drawn a “red line,” threatening military action if Assad used chemical weapons against his own people. However, in 2013, when evidence surfaced of Syrian government troops using chemical weapons in a Damascus suburb, the Obama administration opted instead to broker a deal with Russia’s help, which would result in Syria’s chemical weapons supply being destroyed. The Organization for the Prohibition of Chemical Weapons, the watchdog in charge of overseeing those efforts, has since reported that most of the country’s weapons have been destroyed, and that it expects all production facilities to be destroyed by the summer.

As the war rages on, extremist groups have found greater purchase in the power vacuum left in the country, and the Islamic State group has made major gains in the country in the past two years, culminating in the capture of the city of Raqqa, which has since become the de facto capital of the Sunni militant group. The U.S. has led a coalition of countries in launching airstrikes against ISIS since September. There is no official coordination between the coalition and the Syrian regime, which is also opposed to ISIS, and the U.S. has also accused the Assad regime of deliberately bombing rebel-held areas over ISIS territory, claiming that the two groups enjoy a “symbiotic” relationship.

And since the rise of ISIS, U.S. policy appears to have shifted toward defusing the militant group's power in the region as a primary goal. CIA Director John Brennan told the Council on Foreign Relations last week that “the last thing we want to do is to allow them [extremist groups like ISIS] to march into Damascus.”