With peace talks between the Israelis and Palestinians stalled again, Secretary of State John Kerry and the White House are exhorting both sides to engage and make the necessary concessions to prevent negotiations from collapsing.

Kerry, who has traveled to the Middle East twice in the past 10 days to try to alleviate tensions, was particularly forceful in urging the leaders on both sides to seize the moment.

While traveling in Algeria on Thursday for security talks, Kerry said it's a “critical moment” for the peace process and that he would continue pursuing the negotiations “no matter what.”

But Kerry, as well as White House press secretary Jay Carney, are signaling that the United States is limited in what it can do if both sides remain divided.

Clearly frustrated, Kerry said he could not force Israeli Prime Minister Benjamin Netanyahu or Palestinian President Mahmoud Abbas to continue negotiations.

“You can facilitate, you can push, you can nudge, but the parties themselves have to make fundamental decisions and compromises,” he said. “The leaders have to lead, and they have to be able to see a moment when it's there.”

“You can lead a horse to water but you can't make it drink,” he said. “Now is the time to drink. The leaders need to know that.”

Carney, during his daily briefing with reporters, said there is some progress but acknowledged there is still a “gap” to even restarting the stalled talks. He said it is up to the Israelis and the Palestinians to decide whether to take “the necessary steps to close that gap.”

“These are decisions and steps that the United States cannot make,” he said. “The U.S. cannot impose an agreement on either side.”

In a lighter moment, Kerry, while visiting a Nike store during a youth soccer event in Algiers, joked that he was tempted to use the company's slogan “Just Do It” in challenging Netanyahu and Abbas to see through their differences and get back to the negotiating table.

“But,” he acknowledged, “I don't know if that would have worked so well.”

Wire reports contributed to this story.