TEHRAN, Young Journalists Club(YJC)_Delta Airlines Inc also said it planned to start cutting flights to the United Kingdom.
Southwest, one of the few US airlines still flying a full schedule, said it was "seriously considering" cutting flights.
While airlines scrambled to stem losses and protect jobs, US Treasury Secretary Steven Mnuchin said the government would "immediately" start working with Congress to support the airline and cruise industries, both hard hit by the spiraling crisis.
US Vice President Mike Pence said restrictions on the UK and Ireland will begin Monday at midnight, barring most non-US citizens from entering the United States who have been in those countries within the last 14 days.
They do not bar flights to and from the United States, and Americans and permanent residents can still travel.
United said it would suspend flights to London from Houston and Denver starting Monday. United said it expects to fly three daily flights to London and one daily flight to Dublin through the end of April.
United said it would give a credit for the value of the ticket for any customer whose international travel is disrupted by more than six hours because of schedule changes resulting from government restrictions. Customers who do not use the credit for 12 months will get a refund.
Washington first imposed restrictions on China and expanded them this week to continental Europe, prompting US airlines to cut numerous flights and scramble to shore up capital.
Among cost-cutting measures, US airlines are offering employees voluntary unpaid leaves of absence to match staffing with flights.