LONDON — Another night of terrorism unfolded in Britain on Saturday with two attacks that killed six civilians in the center of the capital, London police said.

At least one of the dead was killed when a van careered onto the sidewalk along London Bridge, mowing down pedestrians.

The London Ambulance Service said it had brought 48 injured to five hospitals.

The police said they killed three attackers, which they believed to be the total number of assailants.

Witnesses reported that at least one man jumped out of the van wielding a large knife and ran into the nearby Borough Market, a popular spot for pubs and restaurants on the southern side of the Thames.