As in Manchester two weeks ago, Londoners were quick to offer assistance to those caught up in the attacks at London Bridge and Borough Market.

Phaldip Singh, who describes himself as an entrepreneur and youth activist, tweeted that Sikh Gurdwaras were open to provide food and shelter for those affected by the attacks. Gurdwaras are places of worship that traditionally serve simple meals to anyone, regardless of their religion.

The Royal Oak pub in Southwark opened its doors to people evacuated from hotels inside the area cordoned off by police. At least one minicab company tweeted an offer of free rides for people stranded in the area.

Britain's official terror threat recently had been lowered from "critical" after the May 22 suicide bombing killed 22 people and injured dozens of others, many of them teenagers, at the pop star Ariana Grande's concert in Manchester, England.

Police say a hit-and-run and stabbings on and near London Bridge officially have been declared a "terrorist incident."

Armed officers flooded the busy area of the city after a van struck multiple people on the bridge. Witnesses also reported seeing people being stabbed by at least one man.

Police say the incidents occurred on the bridge and at Borough Market a short distance away.

The force initially said they were also responding to a reported third incident, in the Vauxhall area of London. But they said later that turned out to be an unrelated stabbing.