The Boston Marathon bombing suspects decided "spontaneously" to bomb Times Square as their next target, New York Police Commissioner Ray Kelly has said.
Mr Kelly said the pair had six explosive devices - a pressure cooker bomb and five pipe bombs - for possible use in an attack in New York.
Mayor Michael Bloomberg confirmed the information on the alleged Times Square plot came from an FBI interview with the surviving suspect Dzhokhar Tsarnaev.
More top news
Barack Obama has returned to the political spotlight, campaigning for Democratic candidates ahead of upcoming elections.
The prime minister said there was a "clear and urgent imperative" to give new impetus to stalled negotiations.
Pollution claimed nine million lives in 2015, with air pollution from vehicles and factories accounting for 6.5m deaths, researchers found.