Speaking alongside European Union High Representative Catherine Ashton in the evening, Kerry said:
"We fully expect the Russians, as they said they would here today, to demonstrate their seriousness by insisting that pro-Russian separatists, who they’ve been supporting, lay down their arms, leave the buildings, and pursue their political objectives through the constitutional processes that the agreement guarantees. No more incidents of this kind should occur, and if they do, it will be clear that it will elicit a response.
"I made clear to Foreign Minister Lavrov today that if we’re not able to see progress on the immediate efforts to be able to implement the principles of this agreement this weekend, then we will have no choice but to impose further costs on Russia."
Under the terms of the agreement, all parties agreed to cease violent and provocative actions, disband all illegal armed groups, and that all occupants of seized buildings must disarm and depart -- and will be granted amnesty.
In order to take immediate action to defuse the crisis, the parties agreed that the OSCE Special Monitoring Mission, which has already been deployed to Ukraine, will "undertake a special role in assisting Ukrainian authorities in local communities in the immediate implementation of the de-escalation measures, that they will do so wherever they are needed the most in the coming days." The EU, U.S., and Russia agreed to provide international monitors.
Kerry emphasized Thursday evening that although the agreement reached constitutes "words on paper, ... [they] will only mean what the actions that are taken as a result of those words produce. So it is absolutely clear now that what is important is that these words are translated immediately into actions, and none of us leave here with the sense that the job is done because the words are on the paper."