The Syrian civil war, now in its fifth year, involves multiple countries with overlapping and at times conflicting agendas. Competing visions of how to manage the conflict, which has led to a major global refugee crisis as well as the rise of the Islamic State, dominated discussions at the United Nations General Assembly last month. But despite days of meetings and diplomatic maneuvering, the crisis only intensified. Here is where some of the main foreign actors stand.

United States

BACKS: More moderate elements among the rebel forces in Syria.

OPPOSES: The government of President Bashar al-Assad, as well as the Islamic State and other Islamic extremist groups.

HOW IT IS FIGHTING: The United States leads a coalition conducting airstrikes in Iraq and Syria against the Islamic State and other extremist groups. It has been carrying out a covert program to train and equip Syrian rebels and a separate Pentagon program to train the moderate Syrian opposition to fight the Islamic State. The Pentagon program has drawn few recruits.

Russia

BACKS: Mr. Assad, the leader of Syria, which has been Russia’s only persistent ally in the Middle East for decades.