A passenger vehicle was involved in the crash, and the driver was being interviewed, state police said.
One woman was flown to the University of Maryland Medical Center's trauma center in Baltimore, but was still being triaged, the University of Maryland Medical System said in a statement.
Administrators at the School District of Philadelphia and C.W. Henry School did not immediately respond to messages left by PhillyVoice on Monday afternoon. Two passengers - one adult and one child - were airlifted from the crash site with critical injuries. On the other buses were police cadets who helped first responders get patients off the bus and request help, according to fire officials.
According to our media partners at The Baltimore Sun, the bus was operated by Werner Coach, which is based in Pennsylvania. A spokesperson for the Werner told the Sun it was still gathering information about the bus and incident. "We don't know the extent of what happened or how bad anything is, but we're trying to prepare ourselves to offer whatever support is needed", said Corsover. The officers were on their way from Philadelphia to Washington D.C. for a memorial.
Trump on Comey 'tapes': 'I can't talk about that'
President, if there are "tapes" relevant to the Comey firing, it's because you made them and they should be provided to Congress. Trump told NBC News that during their January dinner, he asked Comey if he was under investigation and Comey said he wasn't.
North Korea test fires 'new longer range missile'
If the missile did reach that height and fly that long, it could reach the USA territory of Guam in the Pacific, Wright wrote. Earlier, Japanese officials said the missile landed in the Sea of Japan but outside the country's exclusive economic zone.