Updated: 7:32 p.m.

Sen. Claire McCaskill warned the House Armed Services Committee on Thursday that she will strongly oppose its version of the Defense authorization bill when it comes to the Senate because it contains provisions she said are tantamount to earmarks.

“I will be working with my colleagues to ensure that no similar attempt to add earmarks is pursued in the Senate,” the Missouri Democrat wrote in a letter to Chairman Buck McKeon (R-Calif.) and ranking member Adam Smith (D-Wash.). “If necessary, I will also seek language in a conference between the House and Senate that will ensure that any earmarks included in your bill, should they survive to become law, will undergo the most extensive scrutiny and transparency possible upon implementation.”

McCaskill said she believes the bill, which the House debated on Thursday, was structured to get around the House GOP’s pledged moratorium on earmarks.

She said that it was “disappointing and disingenuous” that Armed Services had “instituted a process that allows members of your Committee to circumvent the ban through the use of non-transparent amendments that effectively act as traditional earmarks.”

Based on statements from McKeon’s office and press reports about the process, McCaskill told the Congressmen that it appeared Members of the Armed Services Committee had submitted requests for pet projects before the markup process began and that some of those requests were then written up as amendments that were passed by a voice vote without discussion or debate.

The result, McCaskill wrote, is that the amendment process being used by the committee is actually less transparent than the appropriations earmarking system it replaced.

“Neither exact dollar amounts nor intended recipients of the earmarks can be clearly discerned,” McCaskill said. “Under the pre-moratorium rules, earmark requests were publicly posted and funded earmarks were listed in reports accompanying bills with the sponsor, amount and intended recipient all clearly detailed.”

Josh Holly, the communications director for the Armed Services Committee, defended the panel’s openness in an email Thursday, saying its consideration of the defense authorization was its “most transparent process ever.”

McCaskill’s letter went on to describe a billion-dollar “slush fund” established by the committee called the Mission Force Enhancement Transfer Fund that set aside money from cuts to fund its “pet projects.”

As an example of such a project, McCaskill cited an amendment offered by a Congressman with a “nanotechnology-specific academic center” in his district that sought funding for “innovative nanomaterials and nanomanufacturing processes.” The $7 million amendment was passed in a block of others without debate.

“This is tantamount to the classic earmarking process,” McCaskill told the committee heads.