The union representing the city's 4,300 white-collar workers voted without opposition late today to authorize a strike if contract negotiations stall beyond July 15.

After the vote, about 1,000 members of District Council 47 of the American Federation of State, County and Municipal Employees walked out of Benjamin Franklin High School chanting, "We want a contract!" The vote came a day after the contract expired and the union signed an agreement with the city to extend current contract terms for two weeks.

"We are not satisfied with the pace of negotiation," union president Cathy Scott said. The city has not responded in writing to any of the organization's contract proposals, she said.

Mayor Nutter and members of his negotiating team have kept contract talks out of the public spotlight.

Contracts with four unions representing city workers expired at 12:01 a.m. today. AFSCME District Council 33, the city's blue-collar union of 9,400 members, has agreed to keep negotiating with no immediate labor interruptions. Unlike District Council 47, it has not called a strike-authorization vote.

Today's vote allows District Council 47 leaders to call a strike if the negotiating team thinks the talks aren't going anywhere, Scott said.

Nutter's administration is moving more slowly with the two other groups with expired contracts: Lodge 5 of the Fraternal Order of Police and Local 22 of the International Association of Fire Fighters. Neither can legally strike, so those negotiations will be subject to binding arbitration.

District Council 47 is scheduled to resume negotiations with city officials Monday.

Contact staff writer Joelle Farrell at 610-627-0352 or jfarrell@phillynews.com.