A tanker carrying crude oil from Iraqi Kurdistan was anchored near the Port of Galveston, Texas, on Sunday, a delivery that has infuriated Baghdad, which has threatened to sue anyone who buys the black gold.

The Iraqi government sees such deals as smuggling, raising questions about Washington's commitment to preventing oil sales from the autonomous region — an area where most people do not speak Arabic but Kurdish, a language that is closer to Persian, and people do not consider themselves to be Arabs.

The Marshall Islands-flagged tanker United Kalavrvta sailed from the Turkish port of Ceyhan in June bound for the Gulf Coast of the U.S.

The ship carries approximately 1 million barrels of crude, which would fetch more than $100 million at international prices. It must undergo a routine safety inspection by the U.S. Coast Guard on before it can unload its cargo, an official said.

Iraqi Kurdistan has been selling its crude without Baghdad's permission since January.

The U.S. government has expressed fears that independent oil sales from Kurdistan could precipitate the breakup of Iraq as the Baghdad government struggles to contain the ultra-hardline Islamic State, a group of Sunni Islamist insurgents who have captured vast areas of the country.

In June, Kurdish forces were able to capture the oil-rich city of Kirkuk in northern Iraq amid the confusion of the onslaught of Islamic State fighters. Kirkuk has long been prized by Iraqi Kurdistan's leaders.

Washington has pressured companies and governments not to buy crude from the Kurdish Regional Government (KRG), but it has stopped short of banning U.S. firms from buying it outright.

The KRG has renewed its push for an independent state amid the latest violence roiling Iraq. Its relationship with Baghdad has deteriorated over what it sees as Prime Minister Nouri al-Maliki's role in stoking the crisis and the long-running dispute over oil sales.

Crude offloading from the United Kalavrvta could begin as early as Sunday, if the tanker passes the Coast Guard inspection "and there are no other issues," said Coast Guard Petty Officer Andy Kendrick.

The Coast Guard was communicating with the U.S. National Security Council, State and Homeland Security departments about the vessel's arrival and status, Kendrick said.

The United Kalavrvta received the oil at Ceyhan from a new Kurdish pipeline.

The ship is too large to move through the Houston Ship Channel, which begins at Galveston, the Coast Guard has said. It will have to offload its cargo onto smaller ships offshore before the oil is delivered to the U.S. mainland.

Trading sources in Texas, New York, London and Geneva have been unable to identify the buyer of the United Kalavrvta's cargo. The oil could go to any one of the many refineries located along the U.S. Gulf Coast.

Al Jazeera and Reuters