While kids this week are excited about Kris Kringle, it's Kevlar that had city cops all smiley and shiny-eyed this morning.

Bulletproof vests saved two SWAT officers who went to a Summerdale home before dawn to arrest a shooting suspect, who opened fire on police and hit two.

"He fired through a wall, so they never knew a bullet was coming. We're just very fortunate that we don't have a couple of officers seriously injured or killed," Police Commissioner Charles Ramsey said. "Fortunately, they were each wearing Kevlar-protected vests and helmets ... the bullets did not penetrate."

The drama started about 3:30 a.m., when a tipster called 911 to report that Nasuil "Nas" Martinez was in a rowhouse on Sanger Street near Summerdale. Police have been hunting Martinez, 20, since Dec. 10, when he allegedly shot Officer Kevin Gorman during a foot chase in North Philadelphia. Gorman had stopped Martinez for speeding, and Martinez allegedly jumped from the car and sprinted away, prompting Gorman's pursuit.

Today, SWAT officers swarmed the home about 4:30 a.m. and chased Martinez into the basement, Ramsey said. Martinez began blasting away and hit the two officers, who had returned fire. He then holed up in the basement, sparking a tense three-hour standoff.

Police closed the block, evacuated nearby homes and ordered nearby Fels High School closed, while police negotiators, talking with Martinez on the phone, tried to persuade him to surrender.

Shortly before 7:30 a.m., Martinez agreed to come out. But as he talked with negotiators about how to surrender, the officers heard a gunshot. "Oh, it went off," the officers heard Martinez say, according to Ramsey.

Inside the basement, police found Martinez bleeding badly from the neck. "It appears to be accidental, from what he said," Ramsey said. While Ramsey was briefing reporters, an ambulance sped past, taking Martinez to Temple University Hospital, where he remains in critical condition.

As worried neighbors endured the freezing cold to grab a peek at the action, high-schoolers whooped with joy as officers detoured them and told them of Fels' closure.

"It's horrible. I can't believe that even happened on this block. This neighborhood has changed," said Melissa Pabon, 32, who has lived on the block "off and on" for 17 years.

Another neighbor who asked for anonymity said the house where Martinez shot the cops is owned by a woman who rents out her basement to a steadily changing cast of residents. The owner couldn't be reached for comment.

"They come in and out constantly," the neighbor said. "We don't even know who lives there."

Neighbor Darlene Lane shook her head at the rash actions that landed Martinez in police custody. "He's done," Lane said. "Such a young kid, at a young age, 20 years old, and his life is over."

Court records show that Martinez was a wanted man with a violent history.

A judge issued a bench warrant Oct. 15 after Martinez skipped court for a hearing on his Sept. 28 drug arrest and his Sept. 1 arrest on aggravated assault and related offenses. He was arrested in March 2009 for aggravated assault, gun violations and related offenses; the charges were withdrawn for unspecified reasons.

Gorman was the second Philadelphia police officer shot this year. He was shot in the shoulder and is recovering. Officer Kevin Livewell was shot in the leg in July when gunfire erupted in Kensington after he and his partner stopped a van that fit the description of a vehicle involved in an earlier shooting. The assailants immediately opened fire.