Sens. Jim Inhofe (R-OK) and Marco Rubio (R-FL) have signed onto the letter in which Sens. Rand Paul (R-KY), Ted Cruz (R-TX), and Mike Lee (R-UT), pledged to take action to prevent gun control legislation for coming to a vote.

The letter, dated March 26, was sent to Senate Majority Leader Harry Reid (D-NV) to inform him that the signatories to it would “oppose the motion to proceed to any legislation that will serve as a vehicle for any additional gun restrictions.”

Inhofe and Rubio have added their names to the letter, indicating that they will stand with Paul, Cruz, and Lee in blocking gun control legislation as well.

As matters currently stand, Reid has not issued a statement regarding to the letter. A vote on gun trafficking legislation, expanded background checks, and school security is supposed to take place next month.