After a military exercise in Croatia, around 100 British soldiers have spent the past ten days partying in Zadar, a city on Adriatic coast, where their rowdy behaviour has outraged locals, local media reported.

"Violent, drunk, arrogant -- British soldiers terrorise Zadar citizens for days," read a headline from the local daily Slobodna Dalmacija.

The soldiers, most of them reportedly drunk, peed in the streets, fled cafes without paying bills, fought with locals and vulgarly teased women, according to local media.

Croatian police told AFP they had received several complaints over the unruly behaviour and briefly detained five of the British soldiers, who were fined.

The British embassy in Zagreb said "investigations are being undertaken".

In a statement, a UK army spokesperson said "We apologise to anyone affected in Zadar".

"We do not tolerate poor behaviour and will deal with anyone who falls short of the Army's high standards appropriately," the statement added.

A cafe manager in Zadar told a local newspaper that one of the soldiers "activated the fire extinguisher (while he) was half naked" inside his cafe.

"We had to close the cafe and did not manage to clean it yet. No one of them apologised or offered to pay for the damage. They simply left," the man, whose identity was not revealed, told Slobodna Dalmacija newspaper.

The soldiers "behaved like hooligan fans.... I heard they fled several bars without paying, beat one guy, urinated wherever they could," he was quoted as saying.

Young British tourists already have a reputation for bad behaviour in Croatia, with previous incidents of travellers vomiting in public or walking around scantily clad have led some resorts to introduce fines.

Tourism is a key economic sector for Croatia, which welcomed nearly 19 million visitors last year to its stunning Adriatic coast, which boasts more than 1,000 islands and islets.