"We are grateful for all the support provided... we need more heavy weapons," Umerov said in an embargoed speech released Saturday, "we need them today. We need them now."

At the same conference, President Volodymyr Zelensky had said slow weapons deliveries were hindering his troops' counteroffensive.

Kyiv's forces have since June been involved in a gruelling counterassault to gain back territory seized by Russia in the northeast and south.

"Ukrainian warriors today are sacrifying their lives for the core values of democracy and freedom. They need back up from you, dear partners. And this back up is weapons," Umerov said.

Umerov was appointed this week after Zelensky called for "new approaches" in Ukraine's defence ministry.

The 41-year-old's appointment marks a significant change for Ukraine more than a year and a half into Russia's invasion, and follows corruption scandals in the ministry.

Ukraine launched its counteroffensive after stockpiling Western weapons, but has made limited gains as its troops encounter heavily fortified Russian defensive lines.

It however declared a strategic victory late last month with the capture of the southern village of Robotyne, which it said would pave the way for forces to push deeper towards Moscow-annexed Crimea.