The United States imposes sanctions upon 30 individuals and groups linked to the Islamic State. Fifteen people were designated by the Treasury Department as Islamic State supporters, while 10 individuals and five groups were tagged by the State Department as foreign terrorist fighters.

The designations mean anyone lending the terrorists a hand could be prosecuted under US law. More importantly, they enable the government to freeze the assets of Islamic State supporters. "These sanctions will prevent them from engaging in financial transactions and make it harder for them to travel," said Daniel Glaser, Treasury's assistant secretary for terrorist financing.

Glaser notes the financial sanctions are honored by international institutions. Without access to their assets, supporters could not buy weapons and spare parts for the Islamic State. They would also be unable to back new affiliates.

Among individuals sanctioned by Treasury are Islamic State officials operating in Afghanistan, Pakistan, Libya, Yemen, and Tunisia. Some of them could be placed on the United Nations' Al-Qaeda Sanctions List. That's according to US officials ahead of a meeting on fighting the Islamic State between President Obama and other world leaders at the UN.

The Islamic State and Al Qaeda are believed to have been helping each other. For instance, one member of Al Qaeda in the Arabian Peninsula has facilitated the travel of Islamic State members from Yemen to Syria, according to Treasury.

The terrorist groups sanctioned by the State Department are located in Algeria, Indonesia, Egypt's Sinai Peninsula, and Russia's Caucasus region. 

The sanctions are based upon intelligence gathered by the Central Intelligence Agency, as well information supplied by other countries, including Russia.

Obama administration officials say the diverse background of these individuals and groups reflects the global nature of the Islamic State threat.

From Syria and Iraq, where it occupies terroritories, the group's influence has spread into other parts of the Middle East, Europe, and Asia.

A senior administration official says the Islamic State raises much of its funds from oil sales, taxation, and extortion in areas under its control. Its oil revenue alone amounts to some $500 million each year.

"That creates a unique problem for us," according to the official. "How we're dealing with that problem is by trying to financially isolate ISIL within the territory that it controls so that its financial resources do not turn into financial strength."