BATROVCI, Serbia A day after Croatia joined the European Union, a glitch in its EU-standard customs software caused huge delays at the border with Serbia, the bloc's new external frontier.
Some 1,300 trucks were stuck on Tuesday in a 15 km (10 miles) long queue at the Batrovci crossing just inside Serbia, which lies along Europe's main transit road from Turkey to Western Europe.
The drivers, mostly from southeastern Europe, said they were worried about the fresh produce they were ferrying, as they had to wait for 12 hours or more to cross.
"We have a huge problem. All of Europe is waiting for us," Bulgarian driver Emil Donev, bound for Italy, told Reuters.
"Customs are not working at all, the police will not let us leave our trucks and we are only moving 200 to 300 meters per hour," he said.
The problems with the new software were quickly fixed but it will take two or three days for commercial traffic to return to normal, Serbian customs duty chief Predrag Milikara told Reuters.
A statement from Croatia's customs service said problems were to be expected following the country's accession to the EU.
"It's all part of the adjustment," the statement said.
Croatia became the 28th member of the European Union on Monday, 20 years since the violent collapse of Yugoslavia.
Passenger cars were moving normally.