Verizon Communications Inc. on Friday cut its annual profit forecast as the U.S. wireless carrier added fewer-than-expected monthly phone subscribers in the second quarter, a sign that red-hot inflation has begun impacting its business.

Shares fell 4% before the bell after closing down nearly 3% in the prior session, in which rival AT&T warned that some of its customers were delaying bill payments.

Telecom companies, including Verizon and AT&T, have increased prices for their plans to cushion the impact of higher input costs. The price hike by Verizon in June by way of additional charges was over and above its already pricier plans.

Operating in a highly competitive U.S. telecom sector, Verizon, AT&T and T-Mobile US Inc have been fighting for customers with innovative plans and packages.

Increasing costs have been a concern for Verizon, which had warned in the first quarter that costs would surge above the company's expectations.

"As the market leader, in a very competitive industry, we are determined to improve our operational and financial performance for the second half of the year," Chief Executive Hans Vestberg said in a statement.

The wireless carrier added only 12,000 net phone subscribers who pay a monthly bill in the quarter ended June 30 compared with FactSet estimates of 150,800 additions. In the first quarter, Verizon had lost about 36,000 subscribers.

The company now expects 2022 adjusted earnings per share in the range of $5.10 and $5.25 per share, lower than the prior outlook of $5.40 to $5.55.