(CNN) Sen. Susan Collins, a member of the Senate Select Committee on Intelligence, argued that President Donald Trump was not immune to an investigation into his financial dealings by Justice Department special counsel Robert Mueller.

"The President can't set red lines for Bob Mueller," the Republican from Maine told CNN's Dana Bash in an exclusive joint interview that also featured Sen. Lisa Murkowski, R-Alaska.

"Well said," Murkowski added.

CNN reported Thursday that Mueller and his team are now looking into Trump and his associates' financial ties to Russia as they investigate the 2016 presidential election and whether there was any collusion between the Trump campaign and Russian officials.

Asked in a New York Times interview last month if he felt that a probe into his finances would cross a red line or be a breach by Mueller, Trump said "yes." Trump insisted he doesn't make money from Russia, but said that someone from Russia may have purchased real estate from him.

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