Ruling conservatives in Iran kept up their criticism of President Mahmoud Ahamdinejad's inner circle on Monday, despite a plea for calm by all-powerful supreme leader Ayatollah Ali Khamenei.

In the latest broadside, Hojatoleslam Mojtaba Zolnour, Khamenei's deputy representative to the elite Revolutionary Guards, accused Ahmadinejad's entourage of seeking to weaken the foundations of the Islamic republic.

Snipers shot dead three supporters of powerful opposition tribal chief Sheikh Sadiq al-Ahmar in Yemen's capital on Monday, a tribal source said, blaming government troops.

"Three of Sheikh (Sadiq) Ahmar's supporters were shot dead by snipers stationed on rooftops near the tribal leader's home in al-Hassaba neighborhood" in north Sanaa, the source said.

U.N. chief Ban Ki-moon called Monday on all parties in the Arab-Israeli conflict to exercise "maximum restraint" and expressed "deep concern" about the shooting on the Golan Heights.

"The secretary-general regrets the loss of life, and extends his condolences to the families of the victims," said statement by Ban's spokesman.

Violence in Baghdad and central Iraq on Monday killed 16 people, including 12 struck by a car bomb driven by a suicide attacker in Saddam Hussein's home town of Tikrit, officials said.

The unrest came three days after attacks at a Tikrit mosque and hospital where victims were being treated killed 24, raising doubts over the capabilities of Iraqi security forces just months before all U.S. forces must pull out.

The U.N. atomic watchdog opens a week-long meeting here Monday, with the United States and its western allies looking to pass a resolution against Syria over its alleged illicit nuclear activity.

The traditional June session of the International Atomic Energy Agency's 35-member board of governors has a heavy agenda, ranging from the upcoming two-year budget to the nuclear disaster in Japan.

The parents of Israeli soldier Gilad Shalit, captured by Palestinian militants in Gaza in 2006, plan to file suit in a Paris court against his kidnapping and illegal confinement, his family told Agence France Presse.

The parents of Shalit, who has French citizenship, will file suit in Paris against his "kidnapping and illegal confinement", with the aggravating circumstances that he is "held hostage" and may have "suffered from acts of torture or of barbarism."

NATO pounded Tripoli on Sunday hours after Britain's top diplomat met rebel chiefs in Libya and Russia voiced concerns the alliance's military operation is sliding towards a land campaign.

U.S. Defense Secretary Robert Gates said it was only a matter of time before aides to Libyan leader Moammar Gadhafi abandon him.

Yemen's opposition vowed on Sunday to prevent the return of wounded President Ali Abdullah Saleh from a Saudi hospital, as tens of thousands of protesters celebrated despite doubts over who holds power in Sanaa.

"We will work with all our strength to prevent his return," parliamentary opposition spokesman Mohammed Qahtan told Agence France Presse. "We see this as the beginning of the end of this tyrannical and corrupt regime."

Syrian opposition activists in Europe urged the international community Sunday to increase pressure on President Bashar al-Assad and called for an independent investigation into his regime's deadly crackdown.

The roughly 200 activists gathered in Brussels also said charges should be laid against those responsible for violations of human rights in the repression, and cases brought before the International Criminal Court.

Thirty-eight people, including six members of the Syrian security forces, were killed in 24 hours during clashes in the northwest town of Jisr Shughour, a Syrian rights activist said on Sunday.

"Thirty-eight people were killed in shootings in the region of Jisr Shughour, 10 yesterday and 28 today," Rami Abdul Rahman, head of the London-based Syrian Observatory for Human Rights, told Agence France Presse.