An anti-Israel hacking collective has seized "highly sensitive" nuclear data and satellite imagery from the International Atomic Energy Agency (IAEA), the world’s top nuclear watchdog, according to the website Cryptome.

This is the second time in two weeks that the IAEA’s internal computer systems have been hacked by a group calling itself Parastoo, which is the Iranian word for a swallow (bird).

Parastoo stole the personal information of nearly 200 IAEA scientists and officials last week, including one employee in the United States Department of Energy’s (DOE) Office of Science. DOE is responsible for overseeing America’s nuclear arsenal.

Parastoo now claims to have pilfered reams of documents and personnel information from the nuclear watchdog’s internal "nuclear data section," according to a statement by the group.

It also has obtained "highly sensitive information, Including Confidential ‘SafeGuard' Documents, Satellite Images, Official letters, [and] Presentations," according to the statement.

The hacker group has threatened to release this sensitive information unless the IAEA launches a formal investigation into Israel’s nuclear site, which some believe houses nuclear arms.

"We are demanding IAEA to start an INVESTIGATION into activities at Israel's secret nuclear facilities," the group wrote in its second public statement. "There are many PARASTOOs in the world, seeking for an investigation into Israel's Human-Life threatening nuclear activities."

The IAEA did not respond to a Free Beacon request for comment about the second infiltration of its servers.

Yukiya Amano, the United Nations’ nuclear head, said last week that he did not believe sensitive nuclear safeguards have been comprised as a result of Parastoo’s initial attack, according to Reuters.

Parastoo responded to this charge by launching a second attack last week aimed at penetrating further into the IAEA’s systems, this time its "nuclear data section."

"We're now publishing additional information to prove our ability to gain access to highly sensitive information," Parastoo wrote in its statement.

"IAEA cannot just keep us away by turning off their Servers (either old or new ones!)," the group wrote. "There are plenty more of where this information came from but we guarantee that these information will stay in a very safe place with us."

Parastoo has said that it will safeguard this information as long as the IAEA agrees to investigate Israel’s Negev Nuclear Research Center located near the southern city of Dimona. Israel has not publicly acknowledged having nuclear arms.

Parastoo’s demand appears to be in response to the IAEA’s aggressive investigation into Iran’s clandestine nuclear enrichment program, which is believed to be aimed at building nuclear weapons.

"This information only released to open eyes of IAEA and independent media to real threat of world peace, Israel," the group states. "Our intentions are not to sabotage or misuse such data for any purposes what so ever."

Included in the group’s statement is a link to the IAEA’s internal "nuclear data section." The information, which includes critical technical information needed to acquire access to the system, is meant to prove that Parastoo’s claims are legitimate.

Additionally, Parastoo claims to have at least 15 portions of the IAEA’s system under its control and it lists this information for the public to view.

The group also provides a sample of several documents and satellite images it has seized from the IAEA and lists the email addresses of additional employees.

Parastoo is highly critical of Israel, accusing it of espionage and terrorism in past statements.

Both the language and political positions adopted by Parastoo are similar to dispatches from Anonymous, an anarchic collective of "hacktivists" who engage in cyber-attacks against targets it finds objectionable.

Anonymous recently threatened to launch a "cyber war" against Israel in response to its most recent incursion into the Gaza Strip. It then leaked the personal information of nearly 5,000 Israeli officials.

Details regarding Parastoo’s specific location remain vague.

The group was not publicly known before its first attack and claims to have "many" members likely scattered in various locations.