BECKER, Minn., July 19 (UPI) -- A line of thunderstorms, punctuated by a tornado that flattened a number of mature oak trees, swept through south central Minnesota Saturday.

The storms, which carried tornado watches and warnings, hit the Minneapolis-St. Paul metropolitan area, prompting officials at the PGA Champions Tour 3M Championship in Blaine to suspend the second round of the competition, the Star Tribune reported.

The National Weather Service said there was a possible tornado touchdown near Big Lake in Sherburne County but no significant damage was reported, the Minneapolis newspaper said.

"We got downed power lines; that's it," a Sherburne County Sheriff's Office dispatcher said, adding there was no confirmation of a twister.

The tornado east of Becker, also in Sherburne County, leveled some trees, when it touched down near a barn.

At the 3M golf tournament, the players left the course and spectators were told to take shelter until the storms passed.