– The U.S. is nearing agreement with Russia on establishing additional cease-fire zones in Syria, a key step to finally resolving that country's brutal civil war.

Some officials had suggested agreement could be announced in a meeting between President Donald Trump and Russian President Vladimir Putin on the margins of Friday's Asia summit in Vietnam. But White House press secretary Sarah Huckabee Sanders said a formal meeting wouldn't be held due to scheduling conflicts on "both sides."

Nevertheless, State Department officials said that as the battle in Syria shifts from fighting the largely defeated Islamic State of Iraq and Syria, more attention is focusing on the festering civil war and postwar reconstruction. Russia backs the government of Syrian President Bashar Assad, while the U.S. at least nominally supports an armed opposition.

The U.S. and Russia in July agreed on a cease-fire region in southeastern Syria that has more or less held fast.

"If we can get to another cease-fire zone, that helps get us closer to the Geneva process," State Department spokeswoman Heather Nauert said, alluding to the Geneva-based peace process for Syria led by the United Nations special envoy Staffan de Mistura.

The U.S. and Russia have also been working together on "deconfliction," meaning establishing procedures for avoiding running into each other on the battlefield or on bombing runs in the skies over Syria.

And the U.S. is taking steps to attempt to contain Iran's influence in the region, inviting Saudi Arabia, archrival of Iran, to pay for and oversee large-scale reconstruction in parts of Syria and Iraq once controlled by ISIS. Iran has been allied with Russia and Assad in the war.