DENVER -- Negotiators for U S West and its employees met throughout the day Saturday trying to agree on performance-based pay and other contract issues before the arrival of a midnight strike deadline.
Company spokesman David Beigie said there was a chance the talks would go past midnight if no agreement was made.
"We're willing to continue bargaining in order to get an agreement, but both sides have to decide that," he said.
Carla West, spokeswoman for Communications Workers of America Local 777, said union members were "truly ready to go out."
CWA executives would decide whether to negotiate beyond the midnight expiration of the current three-year contract, "but our membership is very much against extending this," Ms. West said.
Union members organized picket schedules across the 14 states where U S West provides phone service to 25 million customers.
The union represents about 34,000 U S West workers, including operators, customer-service representatives and field technicians.
If a strike is called, customers could see delays in repairs, installation and directory assistance.
Phone service was not expected to be affected since it is largely automated.
A major sticking point is the company's plan to tie pay to a worker's performance.
"It's really where our industry is going in terms of being responsive to customer needs," Mr. Beigie said. "We would hope the union would see that."
For example, the company wants to pay field technicians according to how many trips it takes to complete a job.
Union officials complain that such a scenario would penalize workers for matters out of their control, such as weather or outdated maps.
U S West officials said the performance-pay plan would boost salaries for some workers by 20 percent.
Union officials said the plan was unfair because workers would have no say in the setting of the standards.
The two sides are also at odds over health care plans, forced overtime and scheduling flexibility.
The issues are similar to those that faced BellSouth and Bell Atlantic, both of which managed to reach tentative agreements with union leaders earlier in the week.