Seven British police officers were arrested in Lithuania's capital Vilnius while on holiday.
The Metropolitan police officers were detained following a brawl during a stag party and are under investigation, Scotland Yard told The Sun (paywall).
A Met police spokesman said: "The directorate of professional standards is aware seven police constables from territorial policing were arrested on Saturday 22 November whilst on leave in Vilnius, Lithuania.
"Inquiries into what has taken place are ongoing but are at an early stage. The DPS will liaise with Lithuanian authorities."
The men were pictured bloodied and stumbling as they were handcuffed and put in police cars in the popular tourist city.
Lithuanian prosecutor Marius Zupkauskas said: "I personally gave them bail after they paid 5,000 Lithuanian Lita which is about £1,000.
"If we decide to charge them they will have to return to Lithuania for a trial."
Earlier this year, a bride and groom spent their first night as a married couple in jail after being arrested at a Manchester hotel following a brawl.
The newlyweds were still in their wedding outfits when they were arrested by police after a row in the reception at the plush Hilton Hotel in Deansgate.
The couple reportedly got into a row with hotel staff as they tried to check in.
Staff had to call for extra help from security guards, and the 25-year-old groom allegedly then attacked a security guard, cutting his face in the fight.