DONETSK, Ukraine — The United States and other nations in the Group of Seven agreed on Friday to “move swiftly” to impose additional economic sanctions on Russia in response to its actions in Ukraine. In a joint statement released Friday night by the White House, the G-7 nations said they will act urgently to intensify “targeted sanctions.” The statement said the G-7 will also continue to prepare broader sanctions on key Russian economic sectors if Moscow takes more aggressive action. The White House said US sanctions could be levied as early as Monday. The announcement came as top Ukrainians spoke of imminent invasion and Moscow said that pro-Russian separatists would not lay down their arms in eastern Ukraine until activists relinquish control over key sites in Kiev. The G-7 nations said they were moving forward on the targeted sanctions now because of the urgency of securing plans for Ukraine to hold presidential elections next month. The penalties are expected to target wealthy Russian individuals who are close to President Vladimir Putin, as well as entities they run. However, the US will continue to hold off on targeting broad swaths of the Russian economy, though the president has said he is willing to take that step if Putin launches a military incursion in eastern Ukraine. A senior Obama administration official said each country in the G-7 would determine their own sanctions. While the sanctions will be coordinated, they will not necessarily be identical, according to the official, who was not authorized to discuss the matter publicly and insisted on anonymity. The White House released the G-7 statement hours after Obama convened a conference call with European leaders to gauge their commitment to additional sanctions. Ben Rhodes, Obama's deputy national security adviser, said in a briefing with reporters that sanctions were possible on individuals with influence in specific sectors of the Russian economy, such as energy and banking. “When you start to get at the cronies, the individuals who frankly control large parts of the Russia economy, and some of the entities under their control, you are imposing a significant economic impact beyond strictly sanctioning an individual,” he said. Tensions were heightened on the ground, with Russian fighter jets reported crossing into Ukrainian airspace and a team of unarmed foreign military observers detained by pro-Russian forces in Slovyansk, the heart of the separatist movement in the east. With last week's Geneva agreement calling on all illegal armed groups to lay down their weapons and hand over occupied cities and facilities in tatters, both sides exchanged threats and warnings Friday. Accusing the West of plotting to control Ukraine, Russian Foreign Minister Sergey Lavrov declared that pro-Russia insurgents in the country's east would only disarm and leave the territory they have occupied if the Ukrainian government clears out a protest camp in Kiev's Independence Square, known as the Maidan, and evicts activists from other occupied facilities. “The West wants — and this is how it all began — to seize control of Ukraine because of their own political ambitions, not in the interests of the Ukrainian people,” Lavrov said. — AP