Media playback is unsupported on your device Media caption Chicago has witnessed a recent increase in violence

Up to 13 people, including a young child, have been wounded in a shooting at a basketball court in Chicago.

A three-year-old boy and several others were in a critical condition after the attack in a park on the city's south side.

Witnesses said one or two gunmen opened fire. Police told local media the boy was the most seriously hurt.

Chicago saw more murders last year than New York City, which has a population three times bigger.

Julian Harris told the Chicago Sun-Times that his three-year-old nephew was wounded in the cheek after gang members opened fire at him and others.

"They hit the light pole next to me but I ducked down and ran into the house," Mr Harris said. "They've been coming round here looking for people to shoot every night."

'Boom, boom, boom'

The boy's grandmother, Semecha Nunn, told the Associated Press news agency he would require "a little plastic surgery, but he's OK".

Senseless and brazen acts of violence have no place in Chicago and betray all that we stand for Rahm Emanuel , Chicago Mayor

The dozen or so injured in the shooting at Cornell Square Park ranged in age from 15 to 41.

An unnamed neighbour told the Chicago Tribune: "Man, it was a lot of shots. Man, boom, boom, boom, boom, boom. A little boy got hit in the face."

On Friday, Police Superintendent Garry McCarthy told the Associated Press news agency an assault-style weapon with a high-capacity magazine was used in the shooting.

Supt McCarthy said several victims are believed to be gang members and that investigators suspect the attack to be gang-related.

Firefighters used hoses to wash blood off the basketball court once police had finished examining the crime scene.

Chicago police officer Amina Greer said 10 ambulances were needed to transport victims to nearby hospitals following the shooting at 22:00 local time (03:00 GMT) on Thursday.

At least two other minors, ages 15 and 17, were among the victims, according to media reports.

Chicago Mayor Rahm Emanuel said in a statement: "Senseless and brazen acts of violence have no place in Chicago and betray all that we stand for.

"The perpetrators of this crime will be brought to justice and prosecuted to the full extent of the law."

'Running scared'

Police spokesman Ron Gaines said no arrests had been made so far. He said victims were being interviewed to determine the circumstances of the shooting.

Media playback is unsupported on your device Media caption Hadiya Pendleton's murder in Chicago this year caught national attention. Her parents spoke to the BBC

Witness Francis John, 70, said she was in her home when the shooting occurred. "A lot of youngsters were running scared," she told AP.

The attack comes nearly three weeks after an outburst of violence in the city left eight dead and 20 injured.

In 2012, the Windy City saw 506 murders, compared with 419 in New York, according to a report this week by the FBI.

The pace of violent crime in President Barack Obama's adopted hometown has slackened this year, amid a major police crackdown.

The number of murders in Chicago was down 21% at 297 so far in 2013, while the number of shootings was down 22% at 1,361, the latest crime report showed.

One Chicago murder this year that caught national attention was that of Hadiya Pendleton, 15.

She was killed at a park just days after performing at a January presidential inauguration event in Washington DC.