June 4 (Reuters) - AT&T ( T ) said late on Tuesday that

an issue that had prevented making some calls to other wireless

carriers had been resolved.

Earlier, AT&T ( T ), Verizon and T-Mobile said

they were all experiencing issues with some calls between

carriers.

"The interoperability issue between carriers has been

resolved. We collaborated with the other carrier to find a

solution and appreciate our customers patience," AT&T ( T ) said in a

statement.

Some customers in multiple states had said they were

unable to complete calls, prompting the Federal Communications

Commission to investigate.

Verizon said in a statement earlier that its network was

operating normally, but some customers in the U.S. Northeast and

Midwest were "experiencing issues when calling or texting

customers served by another carrier."

Tracking website Downdetector.com showed more than 2,300

outage reports as of 5:46 p.m. EDT, with the New York City

borough of Brooklyn, Chicago and Philadelphia among the most

reported locations.

T-Mobile US ( TMUS ) said it was "not experiencing an outage. We are

seeing Down Detector increases with other providers, so this

likely could be challenges our customers are having connecting

with users on other networks."

The FCC and New York Attorney General Letitia James said in

February they were investigating the cause of an AT&T ( T )

outage that month as well as the telecom firm's response. The

outage lasted more than 10 hours and impacted more than 70,000

customers.

AT&T ( T ) credited customers a full day of service for the

outage.