The Ukrainian passport is a document issued for nationals of Ukraine as proof of Ukrainian citizenship. The country issues international passports that are used for travel abroad. Until 2016, Ukraine was also issuing internal passports as a soft booklet that was the primary identification document of Ukrainian citizens within Ukraine. These internal passports are now substituted by a credit card-sized Ukrainian identity card, however previously issued passports still remain valid. Also, legislatively regulated electronic passports are available to Ukrainian citizens within a government-issued smartphone application Diia.