KYIV, Ukraine — Ukraine has engaged in discussions with senior officials from the U.S., France, Britain, and Germany to explore strategies to pressure Russia into consenting to a 30-day ceasefire, according to President Volodymyr Zelenskyy’s chief aide on Thursday, amidst a surge in diplomatic efforts to halt the conflict.

Andriy Yermak, Zelenskyy’s chief of staff, did not specify when the online discussions occurred with U.S. special envoys Steve Witkoff and Keith Kellogg, France’s top diplomatic adviser Emmanuel Bonne, Britain’s national security adviser Jonathan Powell, and Guenter Sautter, a senior adviser to the German leader.

But he said all parties “emphasized that a complete and unconditional ceasefire should be the first step towards a just and sustainable peace.”

“We also discussed instruments of pressure in case Russia refuses the initiative or violates the agreements,” Yermak said on Telegram.

Ukraine has shown willingness to accept a U.S. proposal for an immediate, temporary 30-day ceasefire, which could be prolonged by mutual consent, while accusing the Kremlin of disregarding the plan. Putin has suggested a much shorter ceasefire of only three days — from Thursday to Saturday.

“The Kremlin’s proposal for a three-day truce is not about peace, but about safely holding of the parade in Moscow. This is political manipulation,” Yermak said.

Russia, which launched a full-scale invasion of Ukraine in 2022, is preparing to stage a military parade on Friday to mark the 80th anniversary of the defeat of Nazi Germany in what President Vladimir Putin hopes will be a show of strength.

On Thursday, after the declared ceasefire had come into effect, the skies over Ukraine’s major cities were quiet, though there were reports of clashes in eastern Ukraine.