SALEM - Using a videotape to try to make their case, anti-tax activists accused a union-backed group of harassing citizens who signed petitions to force a statewide vote on the Legislature's tax hike.

At a news conference Thursday, the Taxpayer Defense Fund played a videotape that shows two men cajoling and arguing with petitioners as well as citizens attempting to sign petitions on Oct. 11 in downtown Portland.

The taxpayer group said it has "reason to believe" that one or both men are affiliated with the Voter Education Project, the union-backed organization that has been monitoring the anti-tax drive's activities.

But Patty Wentz, spokeswoman for the Voter Education Project, called the assertion a "ridiculous" lie and said her group had no involvement with either of the two men.

In fact, Wentz said the taxpayer group's own videotape at one point shows her approaching the petition carriers and talking with them. She said she did so to assure the petitioners that Voter Education Project had no connection with the unidentified men.

State Elections Director John Lindback said Thursday his office would look into the allegations, which mark the latest chapter in the political battle over the $800 million tax increase passed by the Legislature.

Sponsors of the drive to overturn the tax have until Nov. 25 to round up at least 50,000 valid signatures to force a Feb. 3 statewide vote on the tax. They said Thursday they have reached that amount but are collecting more to make sure they have a safe margin.

Voter rejection of the tax would trigger $544 million in spending reductions for schools, health care for low-income Oregonians and other programs.

The videotape that was played for reporters Thursday was shot outside the Multnomah County Central Library by private investigators hired by the Taxpayer Defense Fund.

It shows the men in some cases arguing with or yelling at people who were trying to sign the petitions. None of the people in the videotape appeared to be dissuaded from signing, although one woman became visibly agitated and several times appeared to demand to be left alone.

Lindback, while not commenting on the particulars of the allegations, said state election law doesn't make it illegal to try to persuade someone not to sign a petition.

He said that intimidating petition carriers with the threat of bodily harm is against the law, though.

"We are looking at it for any potential violation of civil or criminal law," the state's elections chief said.

Russ Walker, who is the leader of the anti-tax drive, said he believes Voter Education Project was involved in the "harassment" because one of the men later was seen with Wentz inside the library.

Wentz, however, vehemently denied that assertion.

"I have never had a conversation with this individual. I do not know him. I did not enter the library on the day in question," she said.