At least 13 people were shot in nine bloody hours in the city over the weekend — including two teens participating in a memorial walk for a friend killed by a stray bullet, police said.

“It’s obscene and really ridiculous,” Natasha Lewis, 32, said of the violence during the march near her Brooklyn home.

“I’m totally shocked . . . [but] you can’t just back down and say we’re not going to have these marches,” said Lewis.

The two young men, ages 16 and 18, each took a bullet to the leg at around 11 p.m. Saturday on Sutter Avenue while walking in memory of Tyquan “Nookie” Jamison, who was slain in 2010 less than a mile away.

Jamison had been playing basketball with friends near the Discipleship Faith Church of God in East New York when he was killed by a bullet meant for a pal.

A 19-year-old man also was stabbed in the groin during what was supposed to have been a peaceful memorial.

“This is normal for this neighborhood, happens every summer,” Sammy Ali, who works at nearby Lucky Deli, said of the violence.

He said he heard the shots inside the store and ran outside to find the block barricaded by authorities and “cops running everywhere.”

The weekend gunfire spree, which occurred between 5 p.m. Saturday and 2 a.m. Sunday, mostly occurred in Brooklyn. One incident took place in Harlem and another in The Bronx.

The most seriously injured was a 23-year-old man hit by five bullets at 2 a.m. Sunday in front of 345 Shepherd Ave. in East New York. He was rushed to Brookdale Hospital and listed in critical condition.

Other shooting victims included four people wounded at around 8:10 p.m. Saturday during an “Old Timer’s Day” barbecue reunion in St. John’s Park by Troy Avenue in Crown Heights.

Police said a man in a hoodie walked up to the group at the Albany Houses and began firing, wounding three men in their 30s and a 54-year-old woman who was shot in the left leg.

During another incident, at around 1:41 a.m. Sunday on New Lots Avenue in East New York, an 18-year-old man was shot in the leg.

Plainclothes cops patrolling the area heard the shots and came across a 16-year-old wielding a gun and told him to drop it, police said.

After the teen thug refused and turned toward the cop, they fired two rounds but didn’t hit him.

The teen was taken into custody.

Additional reporting by Rich Calder