Kerry said it was "no secret" difficult choices are ahead for negotiators and leaders "as we seek reasonable compromises on tough, complicated, emotional, and symbolic issues."
Appointing Indyk as the U.S. special envoy for Israeli-Palestinian negotiations and saying he was a realist, Kerry said his one-time ambassador "understands that Israeli-Palestinian peace will not come easily and it will not happen overnight. But he also understands that there is now a path forward and we must follow that path with urgency."
Kerry said he and Indyk share the belief that if leaders on both sides "continue to show strong leadership and a willingness to make those tough choices and a willingness to reasonably compromise, then peace is possible."
Indyk called his appointment a "daunting and humbling challenge," and expressed gratitude to Kerry and President Obama "for entrusting me with the mission of helping you take this breakthrough and turn it into a full-fledged Israeli-Palestinian peace agreement."
He said he looked forward to working with Kerry, Palestinian Authority President Mahmoud Abbas, Israeli Prime Minister Binyamin Netanyahu and their teams to achieve the vision of "two states living side-by-side in peace and security."
"Getting to this resumption has also taken the courageous leadership of Prime Minister Netanyahu and President Abbas," Kerry said. "And I salute both of them for their willingness to make difficult decisions."
White House spokesman Josh Earnest said during a media briefing the administration "certainly [is] encouraged that the two parties are coming to Washington and beginning their conversations this evening. But we're also cognizant of the hard work that remains over the next nine months. There are some very serious issues that have to be resolved, and it's not going to be easy, but a journey of 1,000 miles begins with the first step, and we'll take that first step today."
Earnest said there was a role for the United States to play in terms of "encouraging both sides to come to the table, trying to facilitate conversations, and in some cases even cajoling one side or the other to -- to try to move the process forward."
Kerry said, "I think reasonable compromises [must] be a keystone of all of this effort," noting the negotiators were en route to Washington to meet Tuesday. "I know the negotiations are going to be tough, but I also know that the consequences of not trying could be worse."
After the talks Tuesday at the State Department, Kerry is expected to release a statement announcing the start of full negotiations, with the next round of talks expected to be in the Middle East.