More than 20 people were stung and one hospitalized when a swarm of up to 20,000 killer bees invaded a Phoenix mosque Friday afternoon.

The incident occurred at the Muslim Community Mosque near 32nd Street and McDowell Road, ABC 15 reported.

The road outside the mosque was shut down and fire crews dispatched to spray the building with foam in order to quell the swarms of angry bees.

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Attacked: Covered by blankets, worshipers at the Muslim Community Mosque in Phoenix flee the swarm of up to 20,000 killer bees that attacked them Friday afternoon. The bees' nest was located in the mosque's eaves

Foam: Firefighters coated the mosque with a foam to quell the bees. Killer bees, officially known as Africanized bees, are a particularly aggressive strain of bee

The bees had formed a nest under the eaves of the mosque. One mosque worker there toldAzfamily.com that a man had already been booked for Saturday to remove the nest but the bees attacked earlier than expected.

Nearby residents were told to stay in their homes. John Chavarria, one such local, told ABC 15 that he witnessed the attack from his house.

'I don't know, it was just crazy how everyone was running everywhere,' he said.

Miming swatting at bees around his head, he continued: 'They were making some movements like that ... some people would even fall in the grass over there and then they'd get up and start running.

'I can’t believe they had the whole street blocked off for the bees.'

Some worshipers used blankets to protect themselves from the swarm, but more than 20 were stung 'multiple times' and one 24-year-old man hospitalized, although everyone was said to be in stable condition.

One man told Azfamily.com that he was stung on the face in five different places.

The bees are believed to have been disturbed by the mosque's speakers, which are located next to their nest.

Nest: The nest, in the building's eaves, is thought to have been disturbed by the building's speaker system. Bees build new nests around this time of year, and it is suggested people check their homes once a week

Stung: This man told Azfamily.com that he was stung five times on his face. Experts warn that trying to swat away bees will only make them angrier, and that instead people should hide in enclosed spaces such as cars

Killer bees, officially known as Africanized bees, are a particularly aggressive species. They are created by breeding European and African bees.

Joseph Mikesell with Truly Nolen Pest Control told Fox 10: 'It's always a bad situation when you're talking about Africanized bees, because once one bee creates a pheromone which sends off the other bees to attack.'

'What people just need to understand is they cannot outrun them, they're not going to sink under water and stay away from them, they're not going to just knock them off, they need to stay away from them.

'If you see bee activity, get inside - don't try and take care of it yourself, contact a professional and let us take care of the situation.'

Emily Brown, a beekeeper, told Azfamily.com that bees are likely to be especially aggressive now, as this is when new queens split off to form their own hives in stable locations such as eaves and composting bins.

She suggests checking places that might prove attractive to bees once a week.

And as the weather gets warmer, bees will become more productive - and therefore more protective of their homes.

Firefighters told the channel that bee attacks are most likely between now and June, and that if attacked it is important to get into an enclosed space such as a building or car - and don't swat the bees as it will make them madder.