SAN FRANCISCO  Verizon Wireless plans to announce on Tuesday that it will soon begin selling Apple’s iPhone 4, according to a person with direct knowledge of the plans.

The long-expected arrival of the iPhone on Verizon will end years of exclusivity for AT&T and is likely to upend the smartphone market in the United States.

It is not clear how soon after the announcement, which will be made in New York, the phone will be available for sale.

On Friday afternoon, Verizon invited reporters to a news conference on Tuesday morning at Lincoln Center in Manhattan. The company did not say what it planned to announce, but given the timing less than a week after top Verizon executives gave a keynote speech at the Consumer Electronics Show in Las Vegas, speculation in tech circles was rampant that Verizon would announce that it would begin selling the iPhone.