Congress is in recess, with members scattered across the world on trips and back in their districts. But the president began reaching out to a few key members of Congress late this afternoon.
In addition to the calls from the president to leaders, senior Capitol Hill aides tell ABC News that Vice President Joe Biden reached out to a wider ring of senior lawmakers -- including Sen. Lindsey Graham, R-S.C.
National Security Advisor Susan Rice called House Foreign Affairs Committee Chairman Ed Royce earlier this evening with a notification, a GOP Congressional aide told ABC News.
Rep. Peter King, R-N.Y., issued this sign of support on Twitter: "All Americans must stand w/Pres Obama in our war against ISIS - particularly tonight's air strikes in Syria."
Meanwhile, House Homeland Security Chairman Michael McCaul, R-Texas, encouraged unity among the divided Congress, noting that "in times of war and of peace it is important that we come together as a nation."
"To defeat ISIS, we must cut off the head of the snake, which exists in Syria. I support the administration's move to conduct airstrikes against ISIS wherever it exists," McCaul, R-Texas, wrote. "ISIS is not just a threat to the United States - it is a threat to all nations that value human life and decency. We must continue to lead the coalition and utilize all tools available to combat this threat until ISIS is destroyed."
Obama travels to New York Tuesday where he will deliver remarks at the Climate Summit 2014 in the General Assembly Hall.
Obama will also chair a meeting of the United Nations Security Council later this week -- only the second time that a U.S. president has chaired a United Nations Security Council meeting.