U.S. investigators on Sunday were studying possible links between a pair of bombs detonated in New York City and New Jersey over the weekend, although no evidence had yet emerged tying the devices to known extremist groups.
The country was shaken by a trio of attacks over the weekend including a Saturday night bombing that injured 29 in Manhattan and a stabbing attack at a Minnesota shopping mall that wounded nine. While officials described all three as deliberate, criminal acts and were investigating them as potential "acts of terrorism," they stopped short of characterizing the motivation behind any of them until more evidence is uncovered.
A deafening roar and powerful shock rocked Manhattan's popular Chelsea neighborhood late on Saturday after a pressure-cooker bomb packed with shrapnel exploded. A similar, unexploded device, was found a few blocks away later that night.
No international militant group immediately claimed responsibility for the New York blast or a pipe bomb that went off earlier along the route of a Saturday road race in suburban New Jersey. But New York Governor Andrew Cuomo said the act of blowing up a bomb in a crowded area of Manhattan "is obviously an act of terrorism."
No suspects were immediately identified in the New York and New Jersey attacks. But CNN reported on Sunday night that police had reviewed surveillance video showing a man, who was not identified, leaving both devices on Saturday.
Federal Bureau of Investigation experts were examining remnants of the two devices that went off in Chelsea and Seaside Park, New Jersey, some 80 miles (130 km) south of New York City, as well as the undetonated pressure-cooker bomb, the same sort of improvised explosive device that killed three people and wounded more than 260 in the 2013 Boston Marathon bombing.
"The crudity of the devices in all three cases certainly doesn't point to any group that's been developing (improvised explosive devices) for years," said a U.S. official involved in the investigation who requested anonymity to discuss the inquiry.
The United States has experienced a series of deadly attacks over the past year by gunmen inspired by IS, which has been fighting a long civil war in Syria. A man who claimed allegiance to the group fatally shot 50 people at an Orlando, Florida, nightclub in June, six months after a married couple massacred 14 in San Bernardino, California.
