A new poll conducted by the Maine People’s Resource Center shows that Republican presidential candidate Donald Trump has made significant gains in the last month, especially in Maine’s 2nd Congressional District.

The survey showed Democratic candidate Hillary Clinton with a 45 percent to 40 percent lead over Trump statewide, said Mike Tipping, spokesman for the Maine People’s Resource Center. But when third-party candidates Gary Johnson and Jill Stein were introduced into the survey, Trump was in a virtual tie with Clinton.

The survey of 835 likely voters, conducted Sept. 15-17, has a statistical margin of error of 3.4 percentage points.

Maine is one of two states that can split electoral votes by congressional district, but it has never done so. If the four candidates maintain electoral support at the levels shown in the poll, Trump could win one or even three of Maine’s electoral votes, Tipping said.

The poll was conducted for Beacon, a progressive news website and podcast created by the Maine People’s Alliance. The alliance is a progressive advocacy group that often supports the initiatives of the Democratic Party or candidates. The Maine People’s Resource Center is a public opinion research organization, affiliated with the alliance.