Britain has raised to the maximum "critical" level for a terrorist threat in the country after the London Underground bombing. That means an imminent threat of attacks, Reuters reported.

Prime Minister Theresa May warned in a televised statement that armed police officers and soldiers will be moving along the streets in the coming days. "For this period, military will replace police officers in guarding some areas and they will not be publicly available," May said.

According to latest data, 29 people have suffered from burns from the self-made explosive device that exploded in a Parsons Green station train. Responsibility for the assault was taken by the Jihadist group Islamic State.