Israeli forces shoot dead Palestinian in occupied West Bank
"Forces encountered an armed Palestinian who opened fire," an English-language statement on the military's official Twitter account said. "In response to the immediate threat, forces fired towards the suspect."
An initial statement said only that the man was carrying a weapon, was seen as a threat and was shot dead during a search by soldiers for arms caches in the flashpoint city.
The army released a picture of what it claims to be the man's weapon, which appeared to be an improvised machine pistol.
Since October 2015, at least 274 Palestinians have been killed by Israeli fire, at least 33 of them under the age of 18.
Israeli authorities claim most of the Palestinians killed were carrying out knife, gun or car-ramming attacks.
However, rights groups accuse Israel of carrying out "unlawful killings" against Palestinians.
Amnesty International said Israeli forces were displaying "an appalling disregard for human life by using reckless and unlawful lethal force against Palestinians."
The rights group said it sent a memorandum to authorities in Tel Aviv detailing at least 20 cases of "unlawful killings of Palestinians by Israeli forces."
"Palestinians were deliberately shot dead, despite posing no imminent threat to life, in what appear to be extrajudicial executions," Amnesty said.
Agencies contributed to this report.