A 16-year-old boy has died when he was struck by a train moments after a police pursuit ended in the area.
The teenager was killed when he was hit in Enfield, north London, at about 5.30pm.
A Scotland Yard spokesman said officers had been pursuing a Mercedes CLK car - thought to have been uninsured - a short time before the tragedy.
He said two men, aged 21 and 22, were arrested after leaving the vehicle at the crossing.
A third man who fled is classified as missing, he said.
The spokesman said the pursuit lasted a "few hundred yards" and ended when the safety barriers came down at the level crossing.
A British Transport Police spokesman said: "We can confirm that a 16-year-old youth was struck and killed by a train at Enfield Lock crossing.
"Police are currently investigating the incident."