The government-backed developer of the United Arab Emirates' railway network says it has halted progress on the second stage of the project.

Etihad Rail said Tuesday it was suspending the tendering process seeking bids from contractors to develop an extension that would have linked the Emirates' border with Saudi Arabia at Ghweifat with the Omani border at al-Ain.

It says it suspended the process to review "the most appropriate options for the timing and delivery of this phase of the project." It did not elaborate.

Operation of the first phase of the rail network began last month. It carries sulfur from Shah and Habshan in the country's interior to the port of Ruwais.

The OPEC member's economy depends heavily on oil revenues, which have fallen amid a slump in prices.