The International Brotherhood of Teamsters said Saturday that a strike of UPS delivery drivers is still possible after the union said it was negotiating on Friday.

UPS provided a counteroffer to the Teamsters’ demands Friday, hours before the union pledged to go on strike without a new contract.

The union said it had agreed not to strike as negotiations continued into the weekend. 

The union’s current contract expires on July 31 and any new contract must be agreed by July 5 to be ratified before the end of the month.

If no contract is reached by July 5, workers will strike when the contract ends, Teamsters president Sean O’Brien said.

“Our administration has made it clear. We will not be working beyond the expiration date without the contract our members have demanded, and more importantly without the contract our members deserve,” O’Brien said at a press conference Saturday.

Negotiations are focused on the “economic” portion of the five-year labor deal.

Teamster demands include increasing the number of full-time workers, upping wages and improving work conditions.

UPS has agreed to add air conditioning to its trucks, but the parties are split on hiring and compensation policy.

“(UPS can) concede to our demands and give us what we deserve and we will go out there and ratify this agreement. Or they can take the other road where they don’t ratify our demands, they stay loyal to Wall Street and forget about Main Street,” O’Brien said.

“If they do that, they are making a choice to strike themselves. We will put 340,000 strong Teamsters on the streets until we get what we want and then UPS will be responsible for stopping supply chain solutions through this company,” he added.

UPS is the largest delivery company in the U.S. with a market cap of about $154 billion and has over 500,000 employees nationwide. Over 300,000 are members of Teamsters.

The union’s size gives a larger meaning to negotiations, O’Brien said.

“This is the largest bargaining agreement in any private sector union. We have the opportunity, because of the courage and conviction of our rank-and-file members who go to work every single day, to set the tone, to set the standard high for labor. Not just for Teamsters, but for the entire labor movement.”

“UPS, the ball is in their court,” he added.

When reached out to, UPS told The Hill that the company’s focus “remains on the progress we’re making at the bargaining table.”

Teamsters did not respond to a request for comment.