[UPDATE BELOW] It's turning out to be a bad day for pedestrians and bike riders. A tipster just sent us this photo of a cyclist who was hit by a cab near 23rd Street and Lexington Avenue. It's unclear how the accident happened, but we're told the biker was loaded onto a stretcher. Our source adds, "Although the ambulance he was put into hasn't moved in 10 minutes. I'm not sure what that means though. Only saw him move once after he got hit." Over in Flatbush, another accident proved fatal for a cyclist.

All we know at this point is what's come in over the wire: A bicyclist was "struck by a vehicle" at Flatbush Avenue and Duryea Place (map). "Aided is DOA." Meanwhile, in DUMBO, Brownstoner reports that a pedestrian crossing Front Street at Washington Street in Dumbo was struck by a commercial van this morning. Be careful out there, people!

UPDATE: It's being reported that there were actually two cyclists involved in accidents in Brooklyn today. The worst one, mentioned above, killed an unidentified man in his 20s who was riding south on Flatbush Avenue at 9:24 a.m. According to witnesses, he swerved into the opposite lane and collided with a minivan driven by an unlicensed driver. "I thought a building fell down," witness Denise Lovell tells the Post. "There was no scream, because he never had a chance."

Another witness says the cyclist was dragged about 50 yards, and was caught under the van until bystanders lifted it off him. He died at the scene. Some witnesses say the driver was speeding, and another driver who was behind the cyclist tells the Daily News, "The biker crossed the yellow line and swerved to miss the white van, but they both swerved the same way and that's when there was the collision." Police arrested the driver.

Meanwhile, over in East New York, another cyclist was critically injured after getting hit by a Toyota Camry shortly after midnight on Linden Boulevard at the corner of Schenck Avenue. It's being reported that the 21-year old driver stayed at the scene and was not charged.