A massive manhunt was under way Sunday in the United States for two convicted murderers who staged a bold escape from a maximum-security prison in New York, according to dpa. More than 250 officers with the FBI, state and local police were searching in New York and beyond for the two killers, who escaped from Clinton Correctional Facility in northern New York state near the town of Dannemora about 500 kilometres north of New York City. Authorities notified officials in Canada about the jail break, said Major Charles Guess of the New York State Police. Officials were not ruling out they they could still be somewhere nearby, but they also said they might have been met by an accomplice in a car and begun driving south toward Mexico. "We presume that they may have access to a vehicle and may have received assistance," Guess said. "They could be literally anywhere." Authorities also announced a 100,000-dollar reward for information leading to their capture. "The first order of business is to get these killers back," Governor Andrew Cuomo said. David Sweat, 34, and Richard Matt, 48, were discovered missing from their cells Saturday morning, police said. The inmates used power tools to drill through a steel wall, pipes and stone to escape underground, police said. They emerged through a manhole on a street several metres from the prison wall. Before slipping out they shaped dummies out of clothing and put them into their beds to dupe guards. "We went back and pieced together what they did. It was elaborate. It was sophisticated," Cuomo said. Anthony Annucci, the acting commissioner of New York's prison system, said that officials did not know how the inmates got the tools, according to The New York Times. In a final jab at authorities the men left a note with a caricature of a man wearing a cone-shaped hat with the words "Have a nice day!" said Gareth Rhodes, a spokesman for Cuomo. Sweat was sentenced to life for killing a sheriff's deputy and Matt was sent to jail for 25 years to life for three counts of murder, three counts of kidnapping and two counts of robbery. It was the first escape from the maximum-security portion of the prison, which opened in 1865, Cuomo said.