Biden lost his cool on Zelenskyy in June during a phone telephonic conversation, reported NBC News. Biden routinely called Zelenskyy when US announced new aid packages for Ukraine. As per NBC, Zelenskyy kept asking Biden for military aid. Biden was informing Zelenskyy about the military assistance. The Ukraine President kept on asking for extra help, the report said. Further, Biden raised his voice, and asked Zelenskyy to ‘show a little more gratitude’. Biden’s dissatisfaction with Zelenskyy had been building for weeks, the sources said. US President believed that Washington was doing everything possible for Kyiv. Zelenskyy continued to publicly pay attention only to what was not being done.