A couple of US tourists who broke into Rome's Colosseum to enjoy a cold beer with a view have been hit with a hefty fine, police said Wednesday.

The pair, aged 24 and 25, had climbed up to the second ring of the ancient gladiator arena at dawn on Monday, but were spotted by an early riser in the Italian capital, who alerted the police.

They admitted to having broken in to drink a beer, and were given an 800 euro ($905) fine, a police spokesman told AFP, without providing any more details.

It was not clear how they had got into the world-famous 2,000-year-old structure, which before the pandemic was visited by around 25,000 people daily.