The report follows the release of photographs by the United States last week of what it said was a Syrian nuclear reactor capable of producing plutonium built with North Korean help.
Israel destroyed the suspected reactor in a September 6 air strike.
NHK said the dead included officials of the North Korea's communist party unit that exports weapons and military technology and members of the North Korean military unit which made nuclear facilities in the country.
Two or three North Koreans survived the air strike but it is not clear what happened to them afterwards, NHK reported.
Syria has denied the US charge as "a fantasy".
Pyongyang has been reluctant to discuss any transfer of nuclear technology to other countries, notably Syria, as well as to account for its suspected pursuit of uranium enrichment.
'Nuclear revelations will not disrupt arms talks'
North Korea's alleged nuclear cooperation with Syria has already been an issue in nuclear talks and evidence released by US officials will not affect arms negotiations, the top American envoy to South Korea said Monday.
Ambassador Alexander Vershbow told foreign reporters in Seoul that American diplomats had for months been talking to the North Koreans about the intelligence that Washington says shows the North was secretly helping Syria build a nuclear reactor.
Evidence supporting the allegations, including purported photos of the Syrian reactor under construction that matched North Korean designs, were released publicly last week by US officials.
"It has already become a complicating factor," Vershbow said of the Syria allegations, saying that the North Koreans were given some of the information weeks ago.
Washington has been pressing North Korea to come forward with a declaration of all of its nuclear activity as it promised to do at international nuclear talks. US diplomats were in Pyongyang last week to seek a breakthrough on the declaration, which is nearly four months overdue.
Reuters and AP contributed to this report