Acting on a judge's order, Egyptian police detained the sons of former president Hosni Mubarak on Saturday along with three others in connection with insider trading charges for which the five are on trial, security officials said.

They said the arrests were ordered by judge Ahmed Aboul-Fetouh before he adjourned the case's hearings until Oct. 20. The Mubarak sons - wealthy businessman Alaa and Mubarak's one-time heir apparent Gamal - were taken to a prison south of Cairo after the hearing, according to the officials, speaking on condition of anonymity because they were not authorized to brief media.

The detention of the two brothers came as something of a surprise given that the trial has been proceeding without incident. It was not immediately clear if their detention has anything to do with a recent warning to Gamal Mubarak by a newspaper editor close to the government to abandon any political ambitions.

The two sons and their father were sentenced to three years in prison following their conviction of embezzling funds set aside for the restoration and maintenance of presidential palaces, using the money to upgrade their private residences. The sons were released in 2015 for time served, while Mubarak walked free last year. The trio paid back to the state the money they embezzled.

The three were first detained in April 2011, two months after a popular uprising forced Mubarak to step down after nearly 30 years in power. After a long trial, Mubarak was acquitted of killing protesters during the 18-day uprising against his autocratic rule.

The ongoing insider trading trial centers on the buying by the two brothers of a large number of shares in a local Egyptian bank that they allegedly knew was to become the target of a takeover by an Arab Gulf investor, a move that was virtually certain to dramatically drive up share prices.

A Belgian court on Monday ruled that Spanish rapper Valtonyc should not be sent back to Spain, where he was sentenced to prison accused of writing lyrics that praise terror groups and insult the royal family.

The rapper, whose real name is Jose Miguel Arenas Beltran, was supposed to turn himself in voluntarily in May to authorities in Spain, where he faces prison sentences totaling three and a half years, but instead fled to Belgium.

"The judge has decided there will be no extradition and discarded all three charges," his lawyer, Simon Bekaert, told reporters near the court in the city of Ghent.

Bekaert said the judge ruled "there is no terrorism involved, there is no incitement of terrorism, so there is no question of a crime according to Belgian law." He said the judge also found that there is no crime to answer to over insulting the Spanish king and that no threat was made that could warrant extradition.

"I feel good, I am happy. But I am sad for the people in Spain, who unlucky, they don't have justice like me here," Arenas told reporters, in English."

The ruling could re-ignite tensions between Belgium and Spain over extradition demands.

Late last year, Spain dropped a European arrest warrant against former Catalan leader Carles Puigdemont after it became clear that Belgian justice authorities were unlikely to recognize some of the Spanish charges against him.