The United Steelworkers union and two other labor organizations have signed on as members of the civic partnership organized to welcome the G-20 to Pittsburgh, a surprising development amid labor skepticism over the economic policies of the world leaders who will gather here in September.

"I imagine there will be members of the partnership that will have differences of opinion over the agenda for the meeting," said Catherine DeLoughry, senior vice president for communications at the Allegheny Conference, which is coordinating much of the planning for the meeting.

Leo Gerard, president of the union, spoke at a protest rally in London during the G-20's last meeting and has been strongly critical of the group's economic agenda, which he has said undermines wage structures and exploits workers worldwide.

Last month, after the White House announced plans to host the G-20 in Pittsburgh, Mr. Gerard expressed skepticism.

"The G-20, and prior to that the G-8, whatever the G was, bought into what was euphemistically called the Washington consensus of deregulation, laissez-faire economics and I think that was the foundation of the economic collapse," Mr. Gerard said at the time.

He has said earlier that he would like a chance to address the group to state the concerns of organized labor.

Wayne Ranick, a spokesman for the union, was scheduled to be at a press conference today where the Pittsburgh G-20 Partnership was expected to list is expanded roster of members and discuss planning for the expected onslaught of world media as well as leaders from 19 nations and the European Union.

Also joining the G-20 partnership, said Ms. DeLoughry, are the Allegheny County Labor Council of the AFL-CIO, and The Pittsburgh Building Trades Council.

The partnership also said today that it was just shy of its $500,000 fundraising goal to build an infrastructure to handle visitors and tell the Pittsburgh story.

Among the largest donors are Alcoa, Bayer Corp., BNY Mellon and PNC Corp.

"This area is going to be upgraded so that it can support a media relations function. There's going to be an online media center," Ms. DeLoughry said.

She said roughly 1,000 people have contacted the partnership to volunteer services -- tasks that have yet to be figured out, she added.

"As the summer plays out, we'll see," she said. "There will be some cleanup and beautification activities for them."