Update: Energy truce in doubt as Trump warns on weapons, Zelensky warns of retaliation

Ukrainian President Volodymyr Zelensky has warned that Ukraine will retaliate if Russia fails to observe an energy truce.

Addressing the Warsaw Security Forum by video on Monday, he said Ukraine would continue to respond if Russia does not stop attacking energy infrastructure.

US President Donald Trump has announced a truce between Russia and Ukraine halting attacks on energy infrastructure, but has not made public the details of the agreement. The announcement caught Ukraine by surprise, while Russia has not issued a formal response. Ukraine's Western allies, however, have supported the initiative.

Zelensky said he was awaiting details of talks between US and Russian officials, adding that concrete steps by the United States to enforce the truce would be important.

Meanwhile, according to the Financial Times, US officials called Ukraine and European countries on Saturday and Sunday pressing them to stop attacks on Russian oil refineries. European officials said Ukraine was warned that continuing such attacks could halt the PURL mechanism, which helps Ukraine purchase weapons, as well as intelligence sharing. The White House has neither confirmed nor commented on these calls.