(VOVworld) – US Secretary of State John Kerry has raised his voice in support of diplomatic efforts to end the 4-year conflict in Syria and urged countries gathering in Vienna not to make the crisis more complicated.

U.S. Secretary of State John Kerry delivers remarks at the United States Institute of Peace on Nov. 12, 2015 in Washington, D.C. (Photo: usnews.com)

Kerry made the statement on Friday before departing for talks in Vienna on Saturday, seeking a political settlement to the civil war that has claimed around 250,000 lives and triggered the worst refugee crisis since World War II.

Kerry said that it remains uncertain whether a political solution can be achieved. Through the Vienna meeting, the US wants to convey a message of responsibility to all parties involved to avoid more bloodshed.

He said any breakthrough made at the meeting will depend on the military balance and narrowing the differences among the US, Russia, and Iran over the future of Syrian President Bashar al-Assad.

Kerry expressed his belief that all parties, including the US, Russia, Saudi Arabia, and Iran will work “by mutual consent” to establish a transitional body.

As scheduled, the international conference on Syria will take place on Saturday, gathering 17 countries and representatives from the UN, EU, the Arab League, and the Organization of Islamic Cooperation.