An attorney for President Donald Trump on Friday blasted U.S. House Democrats' request for six years of Trump's tax returns as "a misguided attempt" to politicize the tax laws, accusing lawmakers of harassment and interference in IRS audits.

In a statement that mapped out the legal battlefield ahead, William Consovoy said the request, formally filed on Wednesday by U.S. House of Representatives tax committee Chairman Richard Neal, flouts "constitutional constraints."

"The requests for his private tax information are not consistent with governing law, do not advance any proper legislative purpose, and threaten to interfere with the ordinary conduct of audits," Consovoy said.