Former British Labour Prime Minister Keir Starmer has received calls from former defense secretaries and a past prime minister to permit Ukraine to deploy long-range missiles within Russian territory, even in the absence of U.S. support, as reported by the Sunday Times on Saturday.

The appeal was made by five former Conservative defense secretaries—Grant Shapps, Ben Wallace, Gavin Williamson, Penny Mordaunt, and Liam Fox—along with ex-Prime Minister Boris Johnson. They cautioned Starmer that “any further delay will embolden President Putin,” according to the Sunday Times.

Ukrainian President Volodymyr Zelenskiy has been urging allies for several months to allow Ukraine to utilize Western missiles, including long-range U.S. ATACMS and British Storm Shadows, to diminish Moscow’s capacity to conduct attacks.

Starmer and U.S. President Joe Biden discussed the issue in Washington on Friday regarding the potential for Kyiv to use long-range missiles against Russian targets, but no decision was reached.

Some U.S. officials remain skeptical that permitting such missile use would significantly impact Kyiv’s efforts against Russian forces.

President Vladimir Putin has warned that allowing Ukraine to strike with Western-made long-range missiles would mean the West is directly engaging in combat with Russia.