Six people were killed in attacks in central and northern Iraq on Monday, including five who died in a spate of bombings in the former insurgent bastion of Fallujah, officials said.

In Fallujah, just west of Baghdad, three bomb attacks in close succession killed five people and wounded 18 others.

Israel's new unity government could help move forward the stalled peace process, Prime Minister Benjamin Netanyahu said in a letter to Palestinian leader Mahmoud Abbas, Haaretz newspaper reported on Monday.

The letter, which answers an earlier missive from Abbas about the stalled peace process, was delivered on Saturday, but so far, no details of its content have been made public.

Liberal civil society groups in Gulf States called Monday on Saudi and Bahraini leaders to postpone plans to announce a union between them, saying such a step must be preceded by a referendum.

"We urge the Saudi and Bahraini leaderships to review such a step and calculate the reactions of the two peoples," the Gulf Forum for Civil Societies said in a statement signed by its secretary general Anwar al-Rasheed.

In a bid to circumvent crippling international sanctions, Iran has been routinely switching off satellite tracking systems on its sea-bound oil tankers, The Washington Post reported late Sunday.

Citing unnamed U.S. officials, the newspaper said the practice has been going on for more than a month.

EU foreign ministers slapped a 15th round of sanctions against President Bashar Assad due to the "appalling violence" in Syria and discussed further support for Kofi Annan's peace plan.

The new European Union sanctions, to take effect Tuesday, mean 129 people and 43 firms or utilities are now targeted by an assets freeze and travel ban for backing the regime's 14-month campaign of relentless repression.

At least 37 people were killed in violence across Syria on Monday, among them 23 soldiers who died in fierce clashes between regime forces and rebels in the central city of Rastan, activists said.

The Britain-based Syrian Observatory for Human Rights said reports indicated that three troop carriers were destroyed in the clashes that began at dawn on the outskirts of the rebel-held city in Homs province, which U.N. observers had toured last month.

Suspected al-Qaida militants blew up a gas pipeline supplying Yemen's Balhaf export terminal in the Gulf of Aden, the second such attack in a month, a government official said on Monday.

"A gas pipeline was blown up near Mayfaa" in Shabwa province in southeast Yemen late on Sunday, the official said, speaking on condition of anonymity.

A candidate in the upcoming poll for a constituent assembly was murdered in Libya's southern desert on Sunday shortly after submitting his registration, a security official said.

"Khaled Abu Saleh was murdered 30 kilometers from Ubari," in the south of Libya, Mohammed Saleh, deputy chairman of the High Security Commission, told Agence France Presse.

Egyptian presidential candidate Ahmed Shafiq's campaign boasted on Saturday that the former air force chief had shot down two Israeli planes during war, as it dismissed accusations of corruption.

Shafiq, former president Hosni Mubarak's last prime minister before an uprising toppled the dictator last year, claimed to have downed the planes during the War of Attrition which Egypt declared between 1969 and 1970.

Syrian opposition leader Burhan Ghalioun on Sunday said he stood ready to hand over the chairmanship of the Syrian National Council (SNC) to others to broaden its appeal.

The SNC is supposed to appoint a new chairman every three months, but Ghalioun has remained leader since the council was set up in October 2011 because of lack of agreement over a successor.