Pittsburgh plane may have been shot down

A Boeing 767 has crashed near Pittsburgh, Pennsylvania.

It is not known if this air crash is related to the three other jets used in today’s spate of terrorist attacks on the US.

The plane came down just north of the Somerset county airport, about 80 miles south east of Pittsburgh.

US anti-aircraft fighters are in place - unconfirmed reports say this plane was shot out of the sky by US defence.

It remains unclear whether this aircraft was the fourth to be hijacked in Boston earlier today.