Russia asserted itself in a long-contested part of Syria on Tuesday after the United States pulled out, giving Moscow a new opportunity to press for Syrian army gains and project itself as a rising power broker in the Middle East.  Russian and Syrian troops drove through a key town where the United States had held sway and picked over abandoned American outposts to announce their presence in the area and deter the Turkish incursion that began last week.

The Russian advance, enabled by President Trump’s decision last week to withdraw, may boost Russia’s Syrian ally, President Bashar al-Assad, while blunting the Turkish incursion. It was a telling demonstration of how influence over the eight-year-old conflict in Syria has shifted from the United States to Russia. But in this case, there appeared to be little balance left in the Americans’ favor. “Look at how they were preparing the base,” a Russian-speaking reporter said in a video shot inside an abandoned American outpost in northeastern Syria, its water tanks, communication towers, tents and fridges full of soda all left behind. “They thought they were going to be here for a long time.”