Cairo: Egypt's top court has temporarily halted all verdicts on a contested deal to transfer two Red Sea islands to Saudi Arabia until it decides who has jurisdiction, a spokesman said on Wednesday.
Egypt's parliament last week backed plans for the uninhabited islands under an accord that attracted widespread public criticism.
But the deal has been caught in a dispute over which institution has the final say after Egypt's highest administrative court rejected it last year.
A separate court suspended the Supreme Administrative Court's verdict.
The agreement now sees two courts and parliament in a battle over jurisdiction.
President Abdel Fattah Al Sisi's government last year announced a maritime demarcation agreement that cedes control of Tiran and Sanafir islands to Saudi Arabia, an ally which has given billions of dollars of aid to Egypt.
Supreme Constitutional Court spokesman Ragab Saleem said: "The Constitutional Court, in cases of contradictory judgments, looks at who has jurisdiction.
"It might see one side has jurisdiction, or that neither side has. It might be under the jurisdiction of another entity."
He said the court was not examining whether the deal was constitutional and did not give a timeframe for a decision.
State media earlier reported the ruling was made to allow time to decide on the constitutionality of the islands deal.
Wednesday's decision only applies to the two courts involved, not to parliament, which has approved the deal.
The Egyptian and Saudi governments say the islands are Saudi but have been subject to Egyptian protection since 1950.
But the plan caused street protests last year from many Egyptians who say their sovereignty over the islands dates back to a treaty from before Saudi Arabia was founded.
Parliamentary leaders and government lawyers say the House of Representatives is the only entity allowed to rule on matters of sovereignty.
But in June last year the country's highest administrative court ruled Egypt's sovereignty must stand.
The Red Sea deal has become politically sensitive for Sisi's government.
Saudi Arabia helped Sisi with aid since he toppled president Mohamed Mursi of the Muslim Brotherhood in 2013.
But Egyptians are eager for economic revival after years of political upheaval and after a devaluation of the Egyptian pound, tax rises and subsidy cuts introduced by Sisi's government that have put pressure on their living costs.
The islands issue touched national pride, prompting thousands of protesters to take to the streets in April chanting "people want the fall of the regime", a slogan little heard since the Arab Spring uprisings of 2011.