[EDITOR'S NOTE: Since publication, this story has been corrected to clarify that the fighters trained in Jordan became members of the ISIS after their training.]

JERUSALEM – Syrian rebels who would later join the Islamic State of Iraq and the Levant, or ISIS, were trained in 2012 by U.S. instructors working at a secret base in Jordan, according to informed Jordanian officials.

The officials said dozens of future ISIS members were trained at the time as part of covert aid to the insurgents targeting the regime of Syrian President Bashar al-Assad in Syria. The officials said the training was not meant to be used for any future campaign in Iraq.

The Jordanian officials said all ISIS members who received U.S. training to fight in Syria were first vetted for any links to extremist groups like al-Qaida.

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In February 2012, WND was first to report the U.S., Turkey and Jordan were running a training base for the Syrian rebels in the Jordanian town of Safawi in the country's northern desert region.

That report has since been corroborated by numerous other media accounts.

Last March, the German weekly Der Spiegel reported Americans were training Syrian rebels in Jordan.

Quoting what it said were training participants and organizers, Der Spiegel reported it was not clear whether the Americans worked for private firms or were with the U.S. Army, but the magazine said some organizers wore uniforms. The training in Jordan reportedly focused on use of anti-tank weaponry.

The German magazine reported some 200 men received the training over the previous three months amid U.S. plans to train a total of 1,200 members of the Free Syrian Army in two camps in the south and the east of Jordan.

Britain's Guardian newspaper also reported last March that U.S. trainers were aiding Syrian rebels in Jordan along with British and French instructors.

Reuters reported a spokesman for the U.S. Defense Department declined immediate comment on the German magazine's report. The French foreign ministry and Britain's foreign and defense ministries also would not comment to Reuters.

The Jordanian officials spoke to WND amid concern the sectarian violence in Iraq will spill over into their own country as well as into Syria.

ISIS previously posted a video on YouTube threatening to move on Jordan and "slaughter" King Abdullah, whom they view as an enemy of Islam.

WND reported last week that, according to Jordanian and Syrian regime sources, Saudi Arabia has been arming the ISIS and that the Saudis are a driving force in supporting the al-Qaida-linked group.

WND further reported that, according to a Shiite source in contact with a high official in the government of Iraqi Prime Minister Nouri al-Maliki, the Obama administration has been aware for two months that the al-Qaida-inspired group that has taken over two Iraqi cities and now is threatening Baghdad also was training fighters in Turkey.

The source told WND that at least one of the training camps of the group Iraq of the Islamic State of Iraq and the Syria, the ISIS, is in the vicinity of Incirlik Air Base near Adana, Turkey, where American personnel and equipment are located.

He called Obama "an accomplice" in the attacks that are threatening the Maliki government the U.S. helped establish through the Iraq war.

The source said that after training in Turkey, thousands of ISIS fighters went to Iraq by way of Syria to join the effort to establish an Islamic caliphate subject to strict Islamic law, or Shariah.