Tariq al-Mutairi, head of the liberal Civil Democratic Movement was detained on his way home early on Wednesday.
Currently no visa or consular services are being provided in Riyadh, Jeddah or Dhahran.
Police sources in Iraq said the victims were civilians who died in an explosion from a truck trailer.
The EU has picked Fernando Gentilini, an official who has worked for NATO in Afghanistan, as the new envoy.
Authorities found 140 detonators, 41 electrical circuits, a remote control device and some cellular telephones hidden inside electrical appliances on the bus.
The Saudis have in the past said a political transition in Syria cannot begin unless President Bashar al-Assad leaves power.
Saudi Arabia sees Iran as its main regional rival and fears that an atomic deal would leave the door open to Tehran gaining a nuclear weapon.
It is the first known dialogue between the Shi’ite Muslim group and the neighbouring Sunni country since Houthis took over last year.
Sweden cancelled a defence cooperation accord with Saudi Arabia last week over rights concerns.
Egyptian law prohibits judges from engaging in politics but critics say the authorities turn a blind eye to those judges supporting the current leader.
The embassy had warned last week that Western oil workers in Saudi Arabia may be the target of militant attacks in the coming days.
The message from the US did not identify the militants or the group they belong to.
The international investment summit in Egypt is expected to see domestic and foreign investments worth up to $12 billion.
The mysterious twitter user, who uses the handle @Mujtahidd, said he wants to expose corruption, injustice and hypocrisy.
The drill in al-Buqa area, which lies in the Houthis’ home province of Saada, involves using different kinds of weaponry, the sources said.
Saudi Arabia said that the move was prompted by remarks by Swedish Foreign Minister Margot Wallstrom about the Kingdom’s regard for human rights.
Shuwaish al-Duwaihi has been replaced by Essam bin Saeed as minister of state and member of the cabinet.
The Australian government said it is verifying whether 18-year-old Melbourne teenager Jake Bilardi has been killed.
Saudi Arabia, the main regional rival of Shi’ite Iran, fears Tehran’s growing influence in Iraq, whose government is Shi’ite-led.
Abdel-Malek al-Houthi accused Gulf states of providing arms and funds to Al Qaeda in Yemen, helping them to flourish in the country.
Qatar had previously said that it would provide $1 billion in reconstruction assistance for Gaza.
The rights group said that the disturbance at the prison was sparked by an assault by security guards on family members trying to visit relatives held at the remote facility.
In his first major public speech, the king vowed to create more private sector jobs and deal with all security challenges.
The king said that European governments must promote “mutual respect” and an “inclusive society”.
Washington has been training and equipping the Iraqi army to fight back the ISIL militants.
Laurent Fabius said that he would chair the meeting which would discuss the problems of Christians and other minorities in the region.
Sultan bin Saeed al-Mansouri said that the word subsidy is often misused and warned that it should not be used without sufficient proof.
The move comes after Sweden’s foreign minister criticised Saudi Arabia’s decision to punish blogger Raif Badawi.
Mubarak Fahad Ali Fahad Al Duwailah is charged with accusing the UAE of being against the Sunni Islam school and for insulting the Gulf country’s leader.
There was no immediate claim of responsibility for the attacks.