Ukraine is warning it will continue efforts to retake control of eastern areas from pro-Russian groups despite warnings from Russia. Tensions have escalated after Ukrainian authorities said they killed five pro-Russian separatists near Slovyansk. Russian President Vladimir Putin has announced new military exercises on the border and warned of unspecified “consequences.” On Thursday, Secretary of State John Kerry warned the United States could take further action against Russia if it does not back down.

Secretary of State John Kerry: “Seven days, two opposite responses, and one truth that cannot be ignored: The world will remain united for Ukraine. So I will say it again. The window to change course is closing. President Putin and Russia face a choice. If Russia chooses the path of de-escalation, the international community, all of us, will welcome it. If Russia does not, the world will make sure that the costs for Russia will only grow. And as President Obama reiterated earlier today, we are ready to act.”