GENEVA - Top diplomats on Thursday laid out a series of steps to tamp down violence and political unrest in Ukraine, even as Western officials publicly doubted Russia's resolve to use its influence to help defuse the crisis in the former Soviet republic.

The potential diplomatic breakthrough, which the Russian foreign minister referred to as "a compromise, of sorts," came after nearly seven hours of negotiations with Secretary of State John Kerry, the Ukrainian foreign minister, and the European Union's foreign policy chief.

Under the agreement, all parties, including separatists and their Russian backers, would stop violent and provocative acts, and all illegal groups would be disarmed. A joint statement made no mention of the presence of what the U.S. has said are 40,000 Russian troops massed on Ukraine's eastern and southern borders. But Kerry said it made clear that Russia is "absolutely prepared to begin to respond with respect to troops," provided the terms of the agreement are observed.

In Washington, President Obama said Russia's stated commitments were only the beginning of a process.

"My hope is that we actually do see follow-through over the next several days, but I don't think, given past performance, that we can count on that," Obama said during a White House news conference. "We have to be prepared to potentially respond to what continue to be, you know, efforts of interference by the Russians in eastern and southern Ukraine."

Obama threatened further economic sanctions and stressed American economic and diplomatic support for the Western-oriented government in Kiev. He ruled out a U.S. military response to help Ukraine fend off Russian incursions.

Obama spoke to British Prime Minister David Cameron later Thursday, and the White House said the two "stressed that Russia needs to take immediate, concrete actions to de-escalate the situation in eastern Ukraine, including by using its influence over the irregular forces in eastern Ukraine to get them to lay down their arms and leave the buildings they have seized."

"We will look for the Russians to quickly follow through on their commitments in Geneva in this regard," a statement from the White House said.

Expectations for the four-way diplomatic session in Geneva were always low, although it marked some diplomatic progress for the Russian and Ukrainian ministers to negotiate directly for several hours. Moscow insists the Kiev government took power in a coup and is illegitimate.

Obama praised the Kiev government's response to the political unrest and violence in Russian-speaking areas of the country, but sounded unconvinced that Russia intends to do anything to roll back the crisis.

"The Russians signed on to that statement," Obama said of the Geneva agreement. "The question now becomes: Will in fact they use the influence that they've exerted in a disruptive way to restore some order?"

The goal, Obama said, is national elections next month and economic reforms promised by the interim Kiev authorities. The election would bring in a new president to replace Viktor Yanukovych, the pro-Moscow president who fled the country in February. Russia moved to annex Crimea from Ukraine shortly afterward.

In addition to disarmament of "illegal groups," the seven-paragraph agreement called for the return of "all illegally seized buildings . . . to legitimate owners" and said that "all illegally occupied streets, squares and other public places in Ukrainian cities and towns must be vacated."

As Ukraine's interim government has previously offered, the agreement also grants amnesty to protesters, "with the exception of those found guilty of capital crimes."

Referring to a portion of the agreement that "rejected all expressions of extremism, racism and religious intolerance, including anti-Semitism," Kerry noted that "just in the last couple of days, notices were sent to Jews in one city indicating that they have to identify themselves as Jews, and obviously the accompanying threat implied is, or suffer the consequences."

"In the year 2014 . . . this is not just intolerable," he said, "it is grotesque."

Reports of the anti-Semitic notices first surfaced in Israeli publications early Thursday, with reports saying the fliers had been distributed by separatist forces in eastern Ukraine.

The deal reached in Geneva also included agreement that the Organization for Security Cooperation in Europe, whose monitors are already on the ground in Ukraine, should "play a leading role in assisting Ukrainian authorities and local communities in the immediate implementation of these de-escalation measures . . . beginning in the coming days." It said that the United States, the EU, and Russia would all provide monitors.

It voiced support for the constitutional reform process currently underway in Ukraine, and insisted that it be "inclusive, transparent and accountable." The process, it said, "will include the immediate establishment of a broad national dialogue, with outreach to all of Ukraine's regions and political constituencies, and allow for the consideration of public comments and proposed amendments."

Kerry called the document "a good day's work," but emphasized that "words on paper" were no substitute for action.