Story highlights In a 17-page letter to Rep. Devin Nunes, Fusion attorneys objected to the subpoenas

The letter is expected to intensify the fight between the two sides

(CNN) The intelligence firm that produced the dossier of memos alleging Russian efforts to aid Donald Trump's presidential campaign is objecting to subpoenas sent by the chairman of the House intelligence committee calling them a "clear abuse of power."

Californian Republican Rep. Devin Nunes signed the subpoenas that were sent on October 4 to Fusion GPS, the firm founded by Glenn Simpson, requesting documents and depositions of key members of the private intelligence firm beginning this week.

"Fusion GPS has cooperated with all legitimate inquiries into Russian interference in the 2016 election," said Joshua Levy, an attorney for Fusion GPS. "Through his improper actions and bad faith, Mr. Nunes has demonstrated that this is not such an inquiry. His subpoenas are a clear abuse of power: They are designed to obfuscate the facts and conjure up rank conspiracy theories at the behest of the president and his most obsequious allies in Congress."

Nunes stepped aside from the House intelligence committee's investigation into Russia's interference in the election in April following an ethics investigation into his handling of classified information. Nunes delegated authority on the Russia matter to Republican Rep. Mike Conaway of Texas. A source familiar with the matter previously told CNN that all Russia-related subpoenas have been approved by Conaway. Conaway at the time confirmed to CNN that he had signed off on the recent subpoenas.

In a 17-page letter to Nunes, attorneys for Fusion said they object to the subpoenas because they violate First Amendment rights to engage in free speech and political activity.

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