In this handout photo provided by the Ukrainian Presidential Press Office, Ukrainian President Volodymyr Zelenskiy speaks to media at a briefing after the Security Council meeting in Kyiv, Ukraine, Tuesday, Feb. 18, 2020. Ukraine and Russia-backed separatists are blaming each other for an outbreak of fighting in the country's rebel-held east. Ukraine's Army Chief of Staff Ruslan Homchak, right, and the Secretary of the National Security and Defense Council Oleksiy Danilov, left, listen. (Ukrainian Presidential Press Office via AP)

In this handout photo provided by the Ukrainian Presidential Press Office, Ukrainian President Volodymyr Zelenskiy chairs a Security Council meeting in Kyiv, Ukraine, Tuesday, Feb. 18, 2020. Ukraine and Russia-backed separatists are blaming each other for an outbreak of fighting in the country's rebel-held east. (Ukrainian Presidential Press Office via AP)

Ukrainian President Volodymyr Zelensky speaks flanked by Ruslan Khomchak, military commander of the Armed Forces of Ukraine, at a briefing following an outbreak of violence with pro-Russian separatists on the frontline, in Kiev on February 18, 2020. - Fierce fighting in eastern Ukraine killed one Ukrainian soldier and wounded several others on February 18, 2020, Kiev said, in the worst clashes in months with pro-Russian separatists. (Photo by GENYA SAVILOV / AFP)

Ukrainian President Volodymyr Zelensky speaks flanked by Ruslan Khomchak, military commander of the Armed Forces of Ukraine, at a briefing following an outbreak of violence with pro-Russian separatists on the frontline, in Kiev on February 18, 2020. - Fierce fighting in eastern Ukraine killed one Ukrainian soldier and wounded several others on February 18, 2020, Kiev said, in the worst clashes in months with pro-Russian separatists. (Photo by GENYA SAVILOV / AFP)

Ukrainian President Volodymyr Zelensky speaks flanked by Ruslan Khomchak, military commander of the Armed Forces of Ukraine, at a briefing following an outbreak of violence with pro-Russian separatists on the frontline, in Kiev on February 18, 2020. - Fierce fighting in eastern Ukraine killed one Ukrainian soldier and wounded several others on February 18, 2020, Kiev said, in the worst clashes in months with pro-Russian separatists. (Photo by GENYA SAVILOV / AFP)

Ukrainian President Volodymyr Zelensky speaks flanked by Ruslan Khomchak, military commander of the Armed Forces of Ukraine, and Oleksiy Danilov, secretary of Ukraine's Security Council, at a briefing following an outbreak of violence with pro-Russian separatists on the frontline, in Kiev on February 18, 2020. - Fierce fighting in eastern Ukraine killed one Ukrainian soldier and wounded several others on February 18, 2020, Kiev said, in the worst clashes in months with pro-Russian separatists. (Photo by GENYA SAVILOV / AFP)

Ukrainian President Volodymyr Zelensky speaks flanked by Ruslan Khomchak, military commander of the Armed Forces of Ukraine, at a briefing following an outbreak of violence with pro-Russian separatists on the frontline, in Kiev on February 18, 2020. - Fierce fighting in eastern Ukraine killed one Ukrainian soldier and wounded several others on February 18, 2020, Kiev said, in the worst clashes in months with pro-Russian separatists. (Photo by GENYA SAVILOV / AFP)