Iraqi intelligence officials offered the AP the letters, as well as the first known photograph of the Nusra Front leader, Abu Mohammed al-Julani, head of one of the most notorious bands of radicals fighting the Syrian government in the country's foreign-hatched conflict.

The officials said they obtained the information about al-Julani after they captured members of another al-Qaeda group in September. They spoke on condition of anonymity because they weren't authorized to speak to journalists.

"I was told by a soldier that he observed some of the workers of the UN and he will kidnap them. I ask God for his success," read an excerpt of a letter given by officials from Iraq's Falcon Intelligence Cell, an anti-terrorism unit that works under Prime Minister Nouri al-Maliki.

The officials said other letters planned the kidnapping and killing of other foreigners, and Syrian and Iraqi civilians.

One UN worker was kidnapped for eight months in Syria and was released in October. Another two dozen UN peacekeepers were briefly held this year. It's not clear if those abductions had any relation to al-Julani's letters.

Syria has been gripped by deadly unrest since 2011. According to reports, Western powers and their regional allies - especially Qatar, Saudi Arabia, and Turkey - are supporting the militants operating inside the country.

According to the United Nations, more than 100,000 people have been killed and millions displaced due to the turmoil that has gripped Syria for over two years.

NTJ/NJF