Facing a subpoena threat, two Democratic-leaning groups whose use of big "soft money" donations is under scrutiny have turned over hundreds of documents to a House committee.

America Coming Together (search) and America Votes (search) are among several partisan groups whose election activities are being investigated by House Administration Committee Chairman Robert Ney (search), R-Ohio.

Only the pro-Republican groups Ney called to testify have agreed to appear. The Democratic groups have refused, saying it appears to be a GOP effort to expose their election plans.

At issue is the groups' use of millions of dollars in corporate, union and unlimited donations known as soft money. A new law broadly bans the use of the big donations in federal elections.

ACT and America Votes spokesman Jim Jordan said the groups turned over about 1,000 pages to Ney's committee Monday including mission statements, fund-raising solicitations and finance reports. They believe it satisfies their obligation to help the panel examine the new law's effectiveness, he said.

Ney has not decided whether to issue subpoenas. He sent letters last month giving the groups another chance to testify voluntarily and urging them to hand over soft money-related documents.

The House inquiry comes as the Federal Election Commission considers new limits for such groups.