The heads of the International Monetary Fund and the U.S. Treasury have visited the Gulf in recent days.

Both IMF Managing Director Christine Lagarde and Treasury Secretary Jacob Lew traveled to Saudi Arabia to speak to the kingdom's rulers, as well as other officials of a regional bloc called the Gulf Cooperation Council.

On Thursday, Lew said in speech in Riyadh that he recognized "the challenge posed to Gulf economies by lower oil prices." Oil prices, which traded above $100 a barrel in mid-2014, have been halved in the time since and now are trading under $50.

Lagarde on Wednesday also noted the low oil prices and said more needs to be done in Gulf countries, including lifting expensive government subsidies on fuel and starting a region-wide value-added tax.