OAKLAND, Calif. -- Just hours after an assault rifle-welding gunman was arrested near a street-corner memorial to a slain teen, gunfire erupted at the dead youth's memorial service at Oakland's St. Anthony’s Church, leaving another teen wounded.

Authorities said the Monday night incident began when gunmen in two cars opened fire on the crowd as people were leaving the East Oakland church. The 13-year-old suffered a foot wound and was taken to a local hospital for treatment.

The eight shots were fired just after 8 p.m. at St. Anthony’s Catholic Church, where a memorial service was being held for 15-year-old Jose Buenrostro. That boy was shot last Wednesday by Oakland police after allegedly pulling out a sawed off shotgun.

“We heard these shots; for a moment we thought they were fireworks,” said bystander Luis del Toro. “I saw people running inside, in towards the church, and then they came outside, trying to run out, and they panicked and started falling to the ground.”

Police say that Jose Buenrostro has gang ties, which is why they were monitoring the ceremony and now fear an escalation in violence.

Father Jesus Nieto-Ruiz, who was leading the service at the time, described a scene of chaos: “You can imagine the church just being packed, and the commotion of all kinds of people, from elders to kids and children and everybody… a very difficult moment,” he said.

Police said that some of the attendees were known gang members, but that no one is in custody, and there were no suspects.

On Sunday, two men with assault rifles were arrested near a street memorial dedicated to Buenrostro.

According to authorities, officers on patrol in East Oakland around 3:10 a.m. allegedly witnessed city resident Marco Mendez, 32, holding an AR-15 assault rifle while standing in the 7800 block of Rudsdale Street.

Mendez reportedly attempted to flee, but was restrained by officers, according to police. Mendez, who police believe is affiliated with a street gang in the area, was arrested on numerous weapons violations.

At about the same time, 26-year-old Andre Piazza, also of Oakland, was arrested after police allegedly saw an AK-47 assault rifle sitting on the front passenger seat of a Nissan Maxima he was about to enter, according to police.

Piazza, who is on parole for drug convictions, was arrested for numerous weapons violations, according to police.

Both men are believed to have been attending the memorial for 15-year-old Jose Luis Buenrostro-Gonzales, who was fatally shot Wednesday near the intersection of 79th Avenue and Rudsdale Street.

Authorities have recovered a total of three rifles on the street in less than a week, police said.

Anyone with information about the possession or location of illegal firearms or information regarding a specific crime is asked to call the Oakland police Crime Stoppers hot line at (510) 777-8572 or (510) 777-3211.