Two other undersea cables were damaged earlier this week north of Egypt, triggering wide Internet outages, hampering businesses and private usage across the Mideast and Asia.
Omar Sultan, chief executive of Dubai's IPS DU, a leading Internet provider in the Emirates, said that the incident Friday was "very unusual."
He said it was not known how the underwater FLAG FALCON cable, stretching between the United Arab Emirates and Oman, had been damaged.
"The situation is critical for us in terms of congestion" on international lines, Sultan told The Associated Press, but refused to speculate on the extent of the damage. DU said in a press release that the cause of the incident "had not yet been identified."
The owner of the FALCON cable, U.K. FLAG Telecom said the cable was cut at 05:59 GMT Friday, about 35 miles off the coast of Dubai, and that a "repair ship has been notified and expected to arrive at the site in the next few days."
The U.K. company is also the owner of one of the undersea cables that were sliced Wednesday in the Mediterranean Sea.
A FLAG official in India, speaking on condition of anonymity because of company policy, said workers were still trying to determine how the Persian Gulf cable was cut. He declined to comment on whether the cut was somehow linked to Wednesday's cut in Egypt, but said he did not believe FLAG's cables were deliberately targeted.
As in the case of the Mediterranean damage, which Egyptian officials said was caused by a ship's anchor when a vessel couldn't dock in the port of Alexandria, there was also speculation that an anchor had sliced the Persian Gulf cable.
DU said the incident "added further complications to the existing cuts on the FLAG Europe-Asia and SEA-ME-WE4 cables" off the coast of Egypt and that the Persian Gulf cut "impacted all international voice calls through the DU network," leading to "severe congestion and degradation of international voice calls."
It said national calls in the Emirates and Internet access were not affected.
DU serves large residential communities of expatriates in the Emirates, including residents on the man-made luxury islands off the coast of Dubai. The Internet provider also serves Dubai International Financial Center.
The full impact of the latest incident on trade in the Mideast's business hub will not be gauged until Sunday, the first working day after the Friday-Saturday Muslim weekend.
In Lebanon, Telecommunications Ministry officials met Friday with representatives of Internet companies operating in Beirut to discuss "a plan to contain the damage caused by a cut in the FLAG cable off Egypt's coast," the state-run National News Agency reported.
Earlier Friday, FLAG said that a repair ship was expected to arrive Tuesday at the site of the damaged cables off the coast of Alexandria, and that repair work would likely take a week.
The Mediterranean cut took place 5 miles from Alexandria, on a stretch linking Egypt to Italy, the company said but gave no explanation why repairs would take so long. Alexandria harbor has been closed for most of this week because of bad weather.
Egypt's Minister of Communications and Information Technology Tarek Kamil said Friday that the Internet service in the country would be up and running to about 80 percent of its usual capacity within 48 hours, revising an earlier statement that this level would be restored by late Friday.
"However, it's not before ten days until the Internet service returns to its normal performance," Kamil told the Friday edition of the state Al-Ahram newspaper. There are eight million Internet users in Egypt, according to a ministry count.
Kamil described Wednesday's damage as an "earthquake" and said the reason behind the cut would only be determined once repair teams with their robot equipment reach the damaged cables.
The official MENA new agency quoted Kamil as saying technicians managed to raise the level of the Internet service Thursday to about 45 percent and that Telecom Egypt would get soon a bandwidth of 10 gigabyte to be increased to 13 gigabyte - close to the country's total capacity of 16 gigabytes.
But Internet access remained sporadic Friday.
The paper also said that state Telecom Egypt on Thursday "sealed a deal" for a new 1,900 mile-long undersea cable between Egypt and France, also through the Mediterranean that would take over 18 months to complete. It did not say who Telecom's partners in the deal were.
Associated Press Writers Barbara Surk, Pakinam Amer and Zeina Karam contributed to this report.