Sen. Rand Paul (Manuel Balce Ceneta/AP) Sen. Rand Paul (Manuel Balce Ceneta/AP)

A top aide to Sen. Rand Paul (R-Ky.), who has been dealing with a series of plagiarism allegations in recent days, acknowledged Tuesday that Paul's staff in some cases failed to properly attribute and quote content pulled from other sources.

"In the thousands of speeches and op-eds Sen. Paul has produced, he has always presented his own ideas, opinions and conclusions," senior adviser Doug Stafford said in a statement. "Sen. Paul also relies on a large number of staff and advisers to provide supporting facts and anecdotes — some of which were not clearly sourced or vetted properly."