OSAKA -- Police arrested three teenagers on Saturday in connection with an assault on four homeless men in a park in Osaka Prefecture the previous day.

The three are suspected of attacking the men, including a 59-year-old who had a rib broken.

Earlier in the day, 13 teenagers turned themselves in to Osaka Prefectural Police. Four more minors were later summoned for questioning over their involvement in the assault, the police said.

The first group of teenagers, aged between 13 and 18 and including junior and senior high school students, said they turned themselves in because the assault was widely reported in the media.

Some of the minors also said they assaulted the men because they got angry after being scolded for the noises their scooters caused, the police added.

According to the police, the four homeless men were attacked as they slept by some 30 teenagers wielding steel pipes and baseball bats at around 2:30 a.m. Friday at a shelter in Hanahaku Memorial Park.

As well as the man who suffered a fractured rib, three others sustained minor injuries. There were about 10 homeless people in the shelter at the time of the incident, but none of the others were hurt.

The victims said the youths attacked them while shouting, "Get out of the park!"

The 13 boys did not take the steel pipes and baseball bats with them when they presented themselves to police.

The park was built for the 1990 International Garden and Greenery Exposition in Moriguchi.