F1 pre-season testing was suspended on Friday due to a bizarre incident involving shattered glass on track in Bahrain.

Two days after the red flag was thrown after a power outage at the circuit, the morning session on the final day was paused with just under an hour to go.

Footage quickly showed the reason, with a heap of shattered glass on the start-finish straight at the Bahrain International Circuit.

The start-finish box, hovering above the circuit, is used to control the starting grid and lights, with footage showing the window of the start-finish box missing on Friday morning.

No more detail has been given yet. The session resumed 10 minutes later.

Charles Leclerc topped the timesheet early on Friday, with Mercedes's Kimi Antonelli in second and McLaren's Lando Norris in third.

Four-time world champion Max Verstappen was fourth-fastest.

Lewis Hamilton drives for Ferrari later on Friday. The first race of the season is in two weeks in Australia (14-16 March).