One cyclist is dead and three are injured after being struck by vehicles in four separate incidents around the GTA Monday afternoon.

A 72-year-old cyclist was struck and killed by a white pick-up truck on Highway 404 south of Mulock Drive in Newmarket just after 2 p.m., OPP Sgt. Kerry Schmidt said.

The Scarborough man was trying to cross the southbound lanes of Highway 404 when he was struck, Schmidt said.

He was pronounced dead on the scene.

North York cyclist struck

Two women and one man were also injured in separate collisions around the city.

Toronto paramedics told CBC Toronto an 18-year-old female cyclist was struck by a truck at Keele Street and Steeles Avenue West around 10 a.m. Monday morning. The woman was transported to a trauma centre with life threatening injuries.

The intersection has re-opened after being closed for almost six hours for the police investigation.

Downtown cyclist struck

Two hours later, another female cyclist was struck by a coach bus according to Toronto Police at Bay Street and Wellington Street West.

Police officers attend the scene after a cyclist was struck by a bus at Bay and Wellington streets, on Sept. 17, 2018, in Toronto. (Sean Davidson/CBC)

The incident happened around noon and the woman was transported to a hospital before police arrived. Toronto Police spokesperson Cst. Allyson Douglas-Cook says the cyclist has non-life threatening injuries.

The intersection of Bay and Wellington has also reopened after being closed for the police investigation.

Scarborough cyclist struck

In Scarborough, another cyclist, a man in his 60s, was hit by a vehicle, Toronto paramedics said.

The incident happened at Midland and Steeles avenues and the man was transported to a trauma centre with serious injuries.