New York Mayor Bill de Blasio tweeted after his news conference:
Once again, we have been shown what our first responders are capable of under extraordinarily difficult circumstances. #eastharlemexplosion
New York City has a new mayor after Bill de Blasio was sworn in at a ceremony at his home just after midnight.
De Blasio's formal inauguration ceremony will take place at on Wednesday at City Hall, where former US President Bill Clinton will administer the oath of office.
Earlier Michael Bloomberg left City Hall for the last time as mayor of New York to applause and cheers.