Max Verstappen and Lance Stroll are under investigation for their involvement in a crash during second practice at the Portuguese Grand Prix.
The pair collided as Verstappen tried to overtake Stroll after they had raced down the pit straight.
Stroll passed Verstappen at the final corner of the previous lap. Verstappen attempted to pass back at the start of the next lap, but Stroll turned in.
Mercedes’ Valtteri Bottas was fastest, with team-mate Lewis Hamilton eighth.
It was a session interrupted by two red flags – one for the incident involving Verstappen’s Red Bull and Stroll’s Racing Point, and another for an earlier stoppage when Pierre Gasly’s Alpha Tauri caught fire.
The staccato running, heightened by the fact that the first half-hour of the session was devoted to a Pirelli-organised test of development tyres, meant the session was unrepresentative of the true competitive order.
It also left the teams short of running and information on the demanding Autodromo do Algarve, which is hosting a grand prix for the first time.
Gasly’s problem interrupted Hamilton’s quick lap on the soft tyres, while Bottas managed to complete his before the session was stopped.
Hamilton did manage to get in another lap before the second red flag, but was 1.3 seconds off the pace.
Bottas had earlier topped the first session, 0.339secs ahead of Hamilton, with Verstappen third.
Verstappen ended the session second fastest, ahead of McLaren’s Lando Norris, Ferrari’s Charles Leclerc and their team-mates Carlos Sainz and Sebastian Vettel.
Ferrari have the latest in a series of aerodynamic upgrades, some developments on their floor being introduced in Portugal following changes to the front of the car at the past two races.