President Biden had his first call as commander-in-chief with Russian President Vladmir Putin on Tuesday and pressed him on the poisoning of opposition leader Alexey Navalny. Biden also urged Putin to renew an arms control treaty—named New START—that expires next month. “They discussed both countries’ willingness to extend New START for five years, agreeing to have their teams work urgently to complete the extension by February 5,” a readout of the call said. “They also agreed to explore strategic stability discussions on a range of arms control and emerging security issues. President Biden reaffirmed the United States’ firm support for Ukraine’s sovereignty. He also raised other matters of concern, including the SolarWinds hack, reports of Russia placing bounties on United States soldiers in Afghanistan, interference in the 2020 United States election, and the poisoning of Aleksey Navalny.”

Navalny, an outspoken critic of Putin, was arrested upon his return to Russia on Jan. 17, after spending months in Germany following an allegedly Kremlin-backed poisoning. “Biden made clear that the United States will act firmly in defense of its national interests in response to actions by Russia that harm us or our allies. The two presidents agreed to maintain transparent and consistent communication going forward,” the readout added.