The Ferrari driver Fernando Alonso has been fastest in practice for this weekend's Monaco Formula One Grand Prix.
The double world champion, also a double Monaco winner in his time at Renault and McLaren, lapped the street circuit with a best time just ahead of the Mclaren of Lewis Hamilton with Nico Rosberg in a Mercedes third fastest.
Championship leder Sebestien Vettel, winner of four of the five races so far, was 5th fastest.
The first session was red-flagged for about five minutes when water began seeping on to the pit straight, seemingly from a leaking pipe beneath the asphalt.
Officials inspected the surface and produced a long implement to turn off a hidden stopcock before allowing practice to resume.