According to the US State Department, US Secretary of State Antony Blinken spoke with Ukrainian Foreign Minister Dmytro Kuleba on Tuesday to address Ukraine’s security concerns in its confrontation with Russia.

According to the State Department, they also discussed ongoing diplomatic efforts to end the crisis that began with Russia’s invasion of Ukraine in late February.

The US imposed penalties on Russian military officers and individuals it accused of being involved in human rights breaches on Tuesday, as well as new restrictions on Moscow’s close friend, Belarus President Alexander Lukashenko.

After his call with Blinken, Kuleba tweeted that he appreciated the fresh round of personal penalties against Russian officials, but that “economic pressure on Russia” needed to be increased.

According to the State Department, Kuleba and Blinken discussed concerns about infrastructure and building damage, as well as civilian deaths and injuries, as a result of the Russian invasion, which Moscow refers to as a “special operation.”

In his tweet, Kuleba continued, “We both agreed it is necessary to ensure the safety and security of nuclear plants in Ukraine.”