AP Photo/Mark Baker

Four people are in custody following shootings at two mosques in Christchurch, New Zealand, during Friday prayers. Witnesses say once shots rang out, chaos erupted, with some worshipers jumping out of windows to escape.

The shootings took place at the Masjid Al Noor and Linwood Masjid mosques. Ahmad Al-Mahmoud told Stuff he was at the Masjid Al Noor mosque when he saw a short, white man wearing a helmet and bulletproof vest enter, opening fire about 10 minutes after prayers started.

Sabir Hussain was at the Linwood Masjid when the imam said several people had been shot. He knew he "was not safe," he told Stuff, so he jumped out the window and hid behind a fence. Another witness, Syed Ahmed, said the gunman started "indiscriminate shooting" while still outside the mosque, and first hit several elderly people sitting in a row of chairs. As he entered the mosque, the gunman was "shouting something," Ahmed told Stuff, but he couldn't understand him "over the screaming." Police have not confirmed the number of casualties. Witnesses at both mosques said children are among the victims.