Sen. Marco Rubio, R-Fla., and Rep. Tom Cotton, R-Ark., said the U.S. should provide military assistance to Ukraine unless Russia quickly withdraws its troops from Ukraine’s Crimea region, but stopped short of calling for U.S. forces to become directly involved.

The freshmen lawmakers, members of their chambers’ foreign relations committees, said that if Russia doesn’t back down in the coming days, Ukraine “will require more than just our moral and financial support.”