The US Treasury added Saudi-born Abd Al-Rahman Muhammad Zafir Al-Dubaysi al-Juhni and Iraq native Abd Al-Rahman Mustafa al-Qaduli to its list of Specially Designated Global Terrorists.
The two were cited for their ties to, respectively, Al-Qaeda operations in Syria, and Qaeda breakaway group the Islamic State of Iraq and the Levant (ISIL).
Al-Juhni is part of a group of senior Qaeda operatives in Syria formed to attack Western targets outside the country and also to mediate tensions between ISIL and the Al-Nusra Front, the local Qaeda affiliate, the Treasury said.
The designation aims to limit their access to financial and business networks by banning any American or American business from dealings with them and freezing any US assets.
Treasury Under Secretary for Terrorism and Financial Intelligence David Cohen said the act sends a message to other Syrian rebels to not work with them
"We are very concerned about Al-Qaeda networks moving money and fighters to extremist groups in Syria. The action sends a strong warning to the legitimate Syrian opposition and those who wish to support it that they must reject the attempts of Al-Qaeda, ISIL, and Al-Nusra to elicit support for their cause by preying on the sympathies of the international community for the plight of the Syrian people.," he said in a statement.