THE New York bomb explosion has seen Donald Trump threatening action against anyone who threatens US security. The blast in the Chelsea district of Manhattan, injured 29 people, and was one of two explosives discovered in New York City. Republican Presidential candidate Trump, who hails from New York, jumped on the issue of national security as he appeared at an election campaign event in Colorado. Mr Trump told supporters: ”Just before I got off the plane, a bomb went off in New York, and nobody knows exactly what's going on."He continued: "We'd better get very tough, folks. "It's a terrible thing what's going on in our world, what's going on in our country. "But we are going to get tough and smart and vigilant and we are going to end it." Democrat rival Hillary Clinton refused to say anything other than that she had been briefed. Mr Trump’s remarks came several hours before New York officials publicly confirmed details of the incident or what caused the explosion although it was later confirmed as “an intentional act”.New York City Mayor Bill de Blasio said the perpetrators were not known, but there was “no evidence at this point” of terrorism. However, a US official said a Joint Terrorism Task Force, a group made up of federal, state and local officials, was called to investigate, suggesting authorities have not ruled out the possibility of a terror connection. The second device was made up of a pressure cooker connected to a cell phone with wires attached. That same sort of device was used by the Boston bombers in 2013. The two Massachusetts brothers behind the attack on the Boston Marathon used pressure cookers packed with explosives and detonated with timing devices to kill three and injure more than 260 people. In an unrelated attack, a pipe bomb was detonated in nearby New Jersey at a charity race on Saturday. The government’s same Joint Terrorism Task Force is also investigating that attack.Mrs Clinton issued a short statement on her campaign plane on the ground in New York, saying she had been briefed on "the bombings in New York and New Jersey". But she said she would wait until she had more information before commenting further. A White House official said President Barack Obama, who was attending a congressional dinner in Washington DC at the time of explosion, had been “apprised of the explosion in New York City, the cause of which remains under investigation”.New York City Fire Commissioner Daniel Nigro said 29 people were hurt in the blast, and 24 of them had been taken to hospitals, including one he described as seriously injured. The rest suffered various cuts, scrapes and other minor injuries. The explosion happened in Manhattan’s bustling Chelsea district just before 9pm local time last night.