The White House on Friday welcomed an agreement signed by Ukrainian President Viktor Yanukovych and opposition leaders aimed at ending a spiral of lethal violence. The agreement is "consistent with what we have advocated in calling for a de-escalation of the violence, constitutional change, a coalition government, and early elections," the White House said in a statement. Yanukovych and the opposition leaders signed the agreement in a bid to end the political crisis in Ukraine, which has left dozens of people dead and hundreds of others injured. The accord envisages constitutional changes that would limit presidential power, and holding early presidential elections this year instead of March 2015, and a formation of a national unity government within 10 days. "Now, the focus must be on concrete action to implement this agreement, which we will be monitoring closely," said the statement. The United States calls for immediate implementation of the initial steps, which include an end to the violence, amnesty and security normalization, and passage of the constitutional package in the parliament, said the statement, adding that the steps would "provide space for the negotiations to begin on formation of a technocratic coalition government." Washington warned that it "remains prepared to impose additional sanctions as necessary," emphasizing that people responsible for the violence and the casualties in Ukraine must be held accountable. Friday's agreement was signed following overnight meetings involving Yanukovych and opposition leaders along with foreign ministers of Poland, France and Germany, and the chairman of Russia's Human Rights Commission. "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 said. On Thursday, the U.S. Department of State authorized the departure of all family members of U.S. government personnel from Ukraine. It also warned U.S. citizens against non-essential travel to Ukraine due to the political unrest and violent clashes between government forces and protesters.