The Senate Armed Services Committee enforced a limit on the U.S. purchase of Russian rocket engines for national security space launches in a move that broke with the panel’s counterpart in the House.

The committee approved a version of the fiscal year 2017 National Defense Authorization Act (NDAA) that would allow the Pentagon to purchase only nine more Russian RD-180 engines to satisfy forthcoming national security satellite launches, continuing a ban established by past defense spending bills. The committee voted to approve the NDAA in a closed markup Thursday and later released a summary of its details.

"The United States shouldn’t be in the business of buying Russian-made rocket engines to the benefit of Vladimir Putin and his cronies, and subsidizing the Russian military industrial base as the nation occupies Crimea, destabilizes Ukraine, bombs U.S.-backed forces in Syria, and provokes U.S. naval forces," Sen. John McCain (R., Ariz.), who chairs the Armed Services Committee, told the Washington Free Beacon. "The good news is we don’t have to."

The committee, citing testimony from military leaders, concluded that maintaining the cap on the purchase of Russian-made engines would not compromise the United States’ access to space given American innovation.

"In testimony before the committee, the secretary of defense, the director of national intelligence, and the secretary of the Air Force each confirmed to the committee that the United States can meet its assured access to space requirements without the use of Russian rocket engines," the summary of the defense authorization bill read.

The bill would also allow as much as half of development funds for a replacement U.S. engine "to be made available for offsetting any potential increase in launch costs as a result of prohibitions on Russian rocket engines."

The Senate’s NDAA breaks with the version approved by the House Armed Services Committee late last month. During its open markup, the House committee approved a measure that would allow for the purchase of 18 Russian-made RD-180 engines—twice the number allowed by the current fiscal year’s defense spending bill.

At the root of the issue is the United Launch Alliance (ULA), a joint venture between Boeing and Lockheed Martin that is contracted by the government to launch national security satellites. ULA uses the Russian-made engines to launch its Atlas V rocket and is working to develop a new rocket that uses only American parts. SpaceX, the only other company that conducts national security space launches for the government, manufactures rockets that use American parts.

Republican Rep. Mike Coffman of Colorado, where ULA is based, introduced the amendment to the House’s NDAA in April that would boost the Pentagon’s purchase of the rockets, which are produced by a Russian manufacturer with ties to President Vladimir Putin. "I just think we want to get off the RD-180, but we want to get off it in a reasonable, responsible way," Coffman said then.

Critics, McCain chief among them, have argued that continued reliance on the Russian engines unnecessarily funnels cash to Putin’s unfriendly government while American companies are on the brink of development.

"There’s no reason for us to line Putin’s pockets and stockpile these when we can get away with nine maybe, nine or ten," Rep. Duncan Hunter (R., Calif.) said during the House committee markup. "When you vote ‘yes,’ you are literally contributing to Russian military modernization."

The purchase of 18 additional RD-18 engines would send an estimated $540 million to Russia.

The Senate’s version of the defense spending bill would also repeal a provision included in last December’s omnibus appropriations bill that allowed the United States to continue purchasing the Russian rocket engines without limit. The measure was inserted into the omnibus by Sens. Richard Shelby (R., Ala.) and Dick Durbin (D., Ill.). McCain accused his colleagues of "scheming" to benefit ULA and its parent company Boeing, which have facilities in their states.

Shelby and Durbin rebuffed McCain’s criticisms by arguing that the provision would allow the United States to transition responsibly to American-made engines without compromising national security. McCain, however, has insisted that there would be no gap in capability because ULA’s Delta IV and SpaceX’s Falcon 9 rockets, both of which use American engines, can launch national security rockets. ULA is pushing to phase out the Delta IV by 2018 for the Atlas V.

Advocacy leaders from Americans for Tax Reform and the Center for Individual Freedom warned Congress against sending more cash to Russia for the RD-180 engines ahead of both markups, arguing that it would reward Russian aggression.

"Rogue nations like Iran remain prime beneficiaries of those Russian rocketry technological advances. The Obama administration’s infamous ‘reset’ attempt with Russia several years ago stands among its most costly foreign policy misjudgments," Timothy Lee, senior vice president for legal and public affairs at the Center for Individual Freedom, wrote in a letter to McCain on Wednesday.

"We cannot afford to repeat that mistake by failing to learn its lesson and foolishly rewarding Russia’s continuing worldwide menace."

The disagreement is one that the House and Senate Armed Services Committees will need to resolve to reach a consensus on next year’s defense spending bill. The House version of the NDAA is set to go to the floor for a full vote next week, and the Senate could take up its version before the Memorial Day recess.

The debate over the purchase of Russian rockets comes as tensions between the United States and Russia heighten. On Thursday, the United States activated a long-planned missile defense shield in Romania to protect Europe from ballistic missile threats from Iran and the Middle East, which drew rebuke from the Kremlin.

"This is not a defense system. This is part of U.S. nuclear strategic potential brought onto a periphery. In this case, Eastern Europe is such periphery," Putin said Friday, according to Reuters.

"Until now, those taking such decisions have lived in calm, fairly well-off, and in safety. Now, as these elements of ballistic missile defense are deployed, we are forced to think how to neutralize emerging threats to the Russian Federation."

Update 2:15 P.M.: Following publication Rep. Mike Coffman (R., Colo.) told the Free Beacon 18 engines are necessary to preserve U.S. competition and access to space.

"On the exact same day the House Armed Services Committee passed my amendment for the 18 RD-180 engines, Ash Carter testified before the Senate Defense Appropriations Subcommittee that the 18 engines are essential to buy enough time for us to develop a domestically-sourced engine, preserve competition, and retain our "assured access into space," Coffman said.