What do I need to show the immigration officer for inspection while applying for 72/144-hour visa-free transit?

A foreign passenger eligible for the transit should provide the immigration officer with his/her own valid passport or other international travel document and onward ticket to a third country (region) with confirmed date and seat within 72/144 hours upon arrival, as well as arrival/departure cards filled out in detail, and should be ready to answer questions raised by immigration officers.