U.N. leader Ban Ki-moon wants Sudan's President Omar al-Bashir to answer war crimes charges, a spokesman said Tuesday as controversy mounted over Bashir's bid to attend a U.N. summit next week.

Bashir, who is wanted by the International Criminal Court for genocide in Darfur, has embarrassed the U.S. government and United Nations by seeking a visa to enter the United States to attend the annual U.N. General Assembly next week.

Former Shiite opposition MP Khalil Marzooq has been detained on charges of "promoting terrorist acts", authorities said on Wednesday, in a move slammed by the opposition as a "dangerous escalation".

Marzooq was questioned by prosecutors in the presence of his attorney and has been ordered held for 30 days for further investigation, Nayef Yousif, head of public prosecution, said in a statement.

Palestinian President Mahmoud Abbas is to meet U.S. President Barack Obama next week, ahead of the opening of the U.N. General Assembly, Palestinian sources said on Tuesday.

At their September 23 meeting, the two men will discuss peace negotiations between the Palestinians and Israel, which resumed earlier this year after a three year hiatus, the sources said.

The United States said Tuesday that Russia is ignoring "the facts" in Syria when it accuses the rebels, rather than the regime, of staging the August 21 chemical weapons attack near Damascus.

Russian Foreign Minister Sergei Lavrov said Tuesday that Moscow believes the August 21 gassing was a "provocation."

U.N. leader Ban Ki-moon said Tuesday he will press the foreign ministers of the United States, Russia, Britain, France and China to take joint action on the Syria crisis at a meeting next week.

He made the announcement as U.N. envoys from the five permanent Security Council members met to discuss a French-drafted resolution on destroying Syria's chemical weapons.

Syrian opposition chief Ahmed Jarba urged the Security Council Tuesday to adopt a resolution under Chapter VII of the U.N. charter allowing use of force to cripple Syria's "war machine."

In a televised speech, Jarba said "ending the killing of Syrian people is only possible by stopping the regime's war machine and barring it from using its aviation, missiles and artillery, and depriving it of its chemical weapons."

Turkish Prime Minister Recep Tayyip Erdogan on Tuesday defended the military's downing of a Syrian helicopter which he said violated its airspace.

"The Turkish Armed Forces did what's necessary," Erdogan told a press conference, a day after its warplanes shot down the military helicopter which was detected two kilometers (1.2 miles) inside Turkish airspace.

Yemeni authorities denied Tuesday the reported death of a child bride on her wedding night, presenting to reporters a girl who claimed she was eight-year-old Rawan and never married.

Last week, the government said it was investigating reports that a child bride had died from injuries suffered on the first night of her marriage to a man in his 40s.

Rights groups Amnesty International and Human Rights Watch urged the United Nations on Tuesday to refer the conflict in Syria to the International Criminal Court.

The statements came after a report by U.N. chemical weapons inspectors confirmed that sarin gas was used in attacks on the outskirts of Damascus on August 21.

Tunisian journalists went on strike Tuesday to protest pressures by the authorities, after a reporter was arrested for accusing the public prosecutor of fabricating evidence against a cameraman.

The national union of Tunisian journalists (SNJT), which called the action, said it was observed by more than 90 percent of its members.