AUGUSTA — Maine’s U.S. senators have voiced concern over President Trump’s unsubstantiated claims that former President Obama had Trump Tower wiretapped during the presidential campaign.

The Portland Press Herald reports Republican Sen. Susan Collins urged Trump to turn over any evidence he might have to support his assertions to the Senate Intelligence Committee.

Both Collins and Independent Sen. Angus King are members of the committee, which has been tasked with investigating Russian efforts to influence last fall’s election.

King called the president’s tweets “unfortunate” at a public forum he hosted in Portland on Sunday.

Collins said the committee’s investigation is in its early stages but she’s seen no evidence supporting Trump’s claims during an appearance Sunday morning on the CBS News program “Face the Nation.”