Under the agreement, which had been extended from April 22, either company can pull out if the deal announced in October 2016 is not completed by the deadline.

"Both sides need to sit down with their clients and their teams and make sure the have down what they need versus what they want," Leon said. "If we are going to get this done prior to that date, we have to move."

The U.S. government opposes the $85 billion (£60.4 billion) deal, arguing that it would hurt consumers because AT&T, which owns pay TV service DirecTV, would have more leverage to raise prices by owning Time Warner's Turner networks.

Wednesday was the fourth day of the trial in U.S. District Court in Washington, that is due to last six to eight weeks. It has been delayed by one snow day.

In testimony that began late Tuesday and ended on Wednesday, Turner networks Chief Executive John Martin said the company had no incentive to hold back its CNN, TBS and TNT content from other distributors if parent Time Warner was bought by AT&T.

The government, however, claims Time Warner would hold back Turner content from distributors that compete with AT&T and DirecTV.

"I would like every distributor to carry every network I have and carry it at 100 percent penetration," Martin said, when cross-examined by AT&T attorney Daniel Petrocelli.

Online streaming services, such as Dish Network Corp's Sling TV and Hulu, which cost subscribers $20 to $40 a month for a select number of networks live and on-demand, are important for Turner because revenue cable and satellite companies is slowing down, he said.

The Department of Justice also asked Marty Hinson, a marketing executive at Cox Communications, about HBO, Time Warner's premium channel. He said it was vital to attract new customers and keep old ones.

When asked about government estimates that if AT&T bought Time Warner each subscriber's average monthly cable bill would rise by 45 cents, Hinson said Cox customers would end up paying "tens of millions of dollars a year for the exact same content."

In his cross exam, Petrocelli asked Hinson if he had ever seen documentation or been told that prices would go up or that it would withhold its programming. Hinson said, "No."

(Reporting By Jessica Toonkel; Editing by Susan Thomas and Richard Chang)

By Jessica Toonkel

Stocks treated in this article : Time Warner, AT&T