A wave of apparently coordinated bombing and shooting attacks in six different provinces across Iraq killed at least 37 people and wounded more than 150 on Thursday, security officials said.

It was the deadliest day in Iraq since March 20, when shootings and bombings claimed by al-Qaida front group the Islamic State of Iraq killed 50 people and wounded 255 nationwide.

U.N. chief Ban Ki-moon has called for an expanded U.N. ceasefire observation mission in Syria even though he says Damascus has failed to adhere to an agreed peace plan.

The U.N. leader said Wednesday he wants 300 unarmed observers to be sent on a three-month mission, in a report to the U.N. Security Council that also said it was "critical" for President Bashar Assad to carry out his commitments.

Turkey's Prime Minister Recep Tayyip Erdogan called Wednesday on Syrian President Bashar al-Assad to send tanks back into barracks to prove that it is fully implementing an international peace plan.

"Unless tanks go back into barracks, we cannot say the six-point peace plan is being implemented," Erdogan said at a press conference televised by private NTV news channel.

U.S. Secretary of State Hillary Clinton on Wednesday warned Syrian President Bashar al-Assad of tougher measures if he squanders his "last chance" by failing to implement a U.N.-Arab peace plan.

During a visit to Brussels, Clinton appeared increasingly concerned over whether a fragile six-day truce will hold and offered Assad a stark choice over whether he pursues peace or resumes crushing a pro-democracy movement.

The powerful Muslim Brotherhood's Khairat al-Shater, barred from Egypt's first post-Arab Spring presidential election, accused the country's military rulers on Wednesday of seeking to stay in power and promised an anti-government protest.

He spoke after the electoral commission confirmed that 10 candidates had been barred from standing, rejecting challenges by him and another Islamist and the old regime's spy chief.

Seif al-Islam will face justice whether he is tried in The Hague or in Libya, International Criminal Court prosecutor Luis Moreno-Ocampo said on Wednesday, insisting the decision lies with the ICC.

Libyan officials, however, remain adamant that he be tried in his country.

Egypt's grand mufti visited Jerusalem's Al-Aqsa mosque on Wednesday, a senior Muslim official said, despite claims by an internationally prominent cleric that such visits are a sop to Israel.

Azzam al-Khatib said Ali Gomaa, Egypt's highest religious authority, "came for a religious visit to Al-Aqsa mosque" along with Jordan's Prince Ghazi bin Mohammed, King Abdullah II's cousin and advisor on religious issues.

A ceasefire to end 13 months of bloodshed in Syria was violated again on Wednesday with 39 people reported dead, despite the government’s latest bid to reassure the United Nations over its willingness to implement the peace plan.

Regime forces killed 20 people in Homs, three in Idlib, four in Daraa, two in Aleppo, two in Hama and one in rural Damascus, the Local Coordination Committees, the main activist group spurring protests on the ground, said.

Iraqi Prime Minister Nouri al-Maliki will visit Iran on Sunday to discuss bilateral issues including energy and water, his spokesman Ali Mussawi told Agence France Presse.

"Maliki will visit Tehran on Sunday, heading a delegation of ministers to discuss key issues like electricity, energy and water," Mussawi said.

An air strike on an al-Qaida position near the southern Yemeni town of Loder killed six militants on Wednesday, the defense ministry said.

"Six al-Qaida terrorists were killed today" in an air raid that targeted one of their positions southeast of Loder, which is the target of an al-Qaida takeover bid, the ministry's news website 26sep.net reported, quoting an unnamed local source.