In competing Manhattan press conferences yesterday afternoon, rival advocacy groups said that (1) there could be a citywide taxi strike in September, and (2) there would not be a strike.

“We are ready to have a 48-hour strike on Sept. 5 and Sept. 6,” said Bhairavi Desai, the executive director of the New York Taxi Workers Alliance, as she stood near a line of taxis outside Pennsylvania Station. “We are ready, willing and able to walk out.”

The Taxi Workers Alliance said in a press release that it wants to work out a resolution with the Taxi and Limousine Commission to avert a strike.

Two hours later, Fernando Mateo, a spokesman for the New York State Federation of Taxi Drivers, said no walkout was ahead.

Standing in front of the Taxi and Limousine Commission office on Rector Street in Lower Manhattan, he said: “Read my lips: There will be no strike.”

The two groups, which have been vying for the right to speak for city cabdrivers, were at odds over a decision by the Taxi and Limousine Commission that requires all of the city’s 13,087 medallion taxis to be equipped by the end of January with new technology including a global positioning system, a credit card system and a monitor that provides passengers with an electronic map. About 1,300 taxis have already had the devices installed.

The G.P.S. that will go in cabs will not be used to navigate routes, but will be connected to meters and track the vehicle’s movements. Commission officials have called it an “electronic trip sheet” and said it could be used to help recover lost property.