Apple Inc appears to be working on a new iPhone model for No. 1 U.S. mobile carrier Verizon Wireless, the Wall Street Journal reported on Monday.

Apple, which currently has an exclusive agreement with AT&T Inc to sell iPhones in the United States, is at work on CDMA-compatible iPhone for Verizon's network, the Journal reported, citing people briefed on the matter.

An Apple spokeswoman said the company does not comment on rumors and speculation.

Verizon Wireless declined to comment. Verizon Wireless is a venture of Verizon Communications Inc and Vodafone Group Plc.

When asked about the report, an AT&T spokesman said: "We have a great relationship with Apple and we don't comment on the specifics of that relationship."

Contract manufacturer Pegatron is scheduled to start mass producing CDMA iPhones in September, the report said, citing one person familiar with the matter. But it was unclear when Apple might start selling that model.

Verizon shares rose nearly 4 percent in after-hours trading from a close of $30.45. Apple shares rose 1.8 percent in extended trading from a close of $232.39. (Reporting by Gabriel Madway and Sinead Carew; editing by Andre Grenon)