Ship-tracking data this week showed the tanker sailing fully-laden towards the Israeli port of Ashkelon before its satellite transponder was turned off on Feb 22.

The United Kalvrvta tanker, carrying 1 million barrels of crude from the semi-autonomous region, became embroiled in a legal dispute in Texas last July after the Kurdistan Regional Government (KRG) looked to ramp up independent oil shipments.

The Iraqi central government challenged the sales, branding them illegal. The KRG protested that independent sales were allowed under Iraq’s constitution.

Employees work at the the oil drilling facility of the joint Turkish Genel Enerji and Canadian ADDAX Petroleum company in the area of Taq Taq, 75 km southeast of the Kurdish city of Arbil in northern Iraq,

The tanker spent several months off the coast of Texas after Baghdad tried to have a U.S. court seize the oil. The ship eventually set sail from Texas in late January, shortly after Baghdad and the KRG agreed a temporary deal on oil sales.

Ship-tracking data this week showed the tanker sailing fully-laden towards the Israeli port of Ashkelon before its satellite transponder was turned off on Feb 22.

It reappeared on Friday unladen. Several of the oil tankers that have carried Iraqi Kurdistan crude from Turkey’s Mediterranean port of Ceyhan have unloaded at Israeli ports, according to ship-tracking data and industry sources.

oil refinery near the village of Taq Taq, in the autonomous Iraqi region of Kurdistan

The KRG has in the past denied selling oil to Israel, which is not formally recognized by the vast majority of Arab states, including Iraq.

A source in the KRG said that all the oil was being delivered to established international trading companies.

Much of the crude being lifted was sold under prepayment deals last year, the source said.

"Gulf Keystone Petroleum", a London-listed oil producer in Iraqi Kurdistan, is exploring a potential sale amid lengthy talks with the KRG over delayed payments for oil exports.