The White House on Friday said it “welcomes” an agreement between Ukrainian President Viktor Yanukovych and opposition leaders after days of violent clashes in Kiev left dozens dead.

But the administration cautioned that it would watch to see if the deal was properly implemented and threatened further sanctions against Yanykovych’s government if it failed to comply with the terms.

The deal is “consistent with what we have advocated in calling for a de-escalation of the violence, constitutional change, a coalition government and early elections,” said the White House in a statement.

“We support the efforts of all those who negotiated this agreement, commend the courageous opposition leaders who recognized the need for compromise and offer the support of the United States in its implementation,” the statement added.

International observers hope the agreement will put an end to the violence in Kiev after government security forces launched a brutal crackdown on groups opposed to President Yanukovych.

Yanukovych killed a potential trade deal with the European Union in favor of closer ties with Russia, sparking months of protests, with opposition groups occupying Independence Square in the heart of the capital.

Yanukovych and opposition leaders signed an accord that was brokered by the EU on Friday, in hopes of ending the political standoff and paving the way to a presidential election later this year. the plan would also limit some of Yanukovych’s powers and establish a national unity government. But according to reports, Moscow, Yanukovych’s key ally, has refused to endorse the plan.

The White House said that it would work to ensure that the agreement was implemented.

“Now, the focus must be on concrete action to implement this agreement, which we will be monitoring closely,” said the statement.

“In this regard, we call for immediate implementation of the initial steps — an end to the violence, amnesty and security normalization, and passage of the constitutional package in the Rada — to provide space for the negotiations to begin on formation of a technocratic coalition government.”

The White House also warned against further violence, saying it was “essential” to ensure “the right of peaceful protest.”

“As we have said, there must be accountability for those responsible for the violence and the casualties that have resulted since the crisis began,” the White House said, “and we remain prepared to impose additional sanctions as necessary.”

Lawmakers expressed cautious optimism, but urged the White House to keep the threat of sanctions on the table.

“While hopeful progress is being made to ease the crisis, the U.S. should have sanctions ready in case there is renewed violence or Yanukovych’s government fails to proceed in good faith,” said Senate Foreign Relations Committee Ranking Member Bob Corker, R-Tenn.

“The Ukrainian military must also continue to refrain from any crackdown of protesters,” he added.

Susan Crabtree contributed.

This story was published at 12:01 p.m. and has been updated.