Ukrainian President Volodymyr Zelenskyy has thanked the Group of Seven nations for offering support to his country during the Russian invasion.

Ukraine's government said Zelenskyy participated in the G7 summit in southern Germany's Schloss Elmau via video link on Monday.

He said Ukraine needs modern and effective missile defense systems, as Russia is intensifying missile attacks on the country.

The president stressed the need to take steps to increase pressure on Russia, including imposing a price cap on Russian oil.

Zelenskyy also suggested creating a global mechanism aimed at confiscating frozen or seized Russian assets.

He said such a mechanism "should become one of the biggest tools to deter other potential aggressors from attacking neighbors."

The president asked the G7 countries to help Ukraine resume grain exports. He also called for support in the expected reconstruction efforts in Ukraine.

US National Security Advisor Jake Sullivan said Washington is working on a plan to provide defense systems to Ukraine in response to a request from Zelenskyy.

Sullivan told reporters at Schloss Elmau that the US is in the process of finalizing a package for Ukraine that includes advanced air defense capabilities.