Sen. Ted Cruz, R-Texas, and Sen. Rand Paul, R-Ky., will work to block a $1 billion Ukraine aid package unless Senate Majority Harry Reid, D-Nev., strips out a controversial measure funding the International Monetary Fund.

The lawmakers told Reid they “intend to object to any floor consideration of Ukraine aid legislation” until the IMF language is pulled from the bill. Rand and Cruz united on the issue just days after tensions ran high between them because of their disagreements on foreign policy.