Major Japanese airports are crammed with thousands of passengers unable to take domestic flights due to problems with airline computer systems.

The delays began Tuesday morning, with major Japanese carrier All Nippon Airways posting a notice on its website apologizing for delays and cancellations due to a "system malfunction."

The airline said Internet check-in, seat selection, new reservations, changes to reservations and payments were not available for domestic flights. It said it was trying to identify and fix the problem as soon as possible.

Four smaller airlines that use the same system — Starflyer, Airdo, Solaseed Air and Ibex Airlines — also reportedly were affected.

Tuesday morning ended a three-day holiday weekend in Japan, likely causing more travelers than usual.

Television news channels showed airports packed with frustrated travelers.