ZAGREB, Croatia (AP) — Outnumbered Croatian police officers fired warning shots into the air and ground with live ammunition when soccer fans returning from a match in the capital attacked them on a highway with iron bars, bats and flares, authorities said Sunday. At least 35 people were injured, including four fans with bullet wounds.

The violence late Saturday happened when a convoy of more than 260 cars and buses was transporting Hajduk Split fans under police escort after their team lost 3-1 to Dinamo Zagreb. The two teams have a fierce rivalry — Split is Croatia’s second-largest city after Zagreb — and Hajduk fans may have been angry because police barred them from entering Zagreb’s stadium with flares and banners.

About 2,000 fans refused to enter the stadium and remained outside throughout the match, police said. As they were traveling back to Split, which is about 355 kilometers (220 miles) south of Zagreb, a group of fans blocked traffic and started attacking officers on a section of the highway on the outskirts of the capital, police said.

The road is the main Croatian highway leading from Zagreb to the Adriatic Sea coast. Police said the fans ignored orders to disperse.