All the victims were Czech nationals. In the pre-dawn accident the bus smashed through a safety barrier that normally separates highway traffic and overturned in the opposite lane close to a tunnel.

The crash scene lies 200 kilometers (124 miles) south of Zagreb on a highway connecting the Croatian capital with the Adriatic coastline.

Most of those injured have been hospitalized in Gospic, a town close to the crash site. The driver reportedly survived.

Three of those most severely injured, including two children, were flown by helicopter to Zagreb, according to Croatian rescue service officials.

In Prague, Czech foreign ministry's spokesman Karel Srol was quoted by the news agency CTK as saying that two injured passengers were in critical condition.

A spokesman for the bus operator, a travel agency in the southern Czech city of Brno, Martin Vasulin, said most of the passengers came from the area, with some also from Prague. Their bus was en route to the Adriatic resort of Basko Polje.

The crash resulted in a temporary highway closure, with major tailbacks in both directions affecting Adriatic coast traffic.

Croatian state television quoted eyewitnesses as saying that the bus had started swaying moments before Saturday's 4 a.m. crash.

ipj/ncy (AP, AFP, dpa)