Al-Qaida's north African branch warned European states including France Thursday against a military bid to rescue hostages kidnapped in Mali, citing "information" of plans for such an operation.

"We send a warning to France, Britain, the Netherlands and Sweden: if they authorize this operation it will mean the death of their nationals and amount to an attempt on their lives," it said in a statement in Arabic.

Russian Security Council secretary Nikolai Patrushev warned that military escalation is likely in Iran, with "real danger" of a U.S. strike, in an interview published Thursday.

He added that Syria, which has refused to break its ties with Tehran, could also be a target for Western intervention.

Two Arab League monitors in Syria have quit, officials said on Thursday as the head of the operation accused an Algerian observer who resigned of making unfounded claims about the operation.

"Two monitors have excused themselves, an Algerian and an Sudanese," Syria operations chief Adnan Khodeir said at Arab League headquarters in Cairo.

Four Americans were being held by security forces after they were stopped for "suspicious" activity in the center of Baghdad on Thursday, the governor of Baghdad province told Agence France Presse.

The two men and two women were driving a BMW with local license plates, rather than diplomatic registration, and were all wearing flak jackets and armed with pistols and automatic weapons, said Salah Abdulrazzaq, who described the group as "gunmen."

Twenty gunmen were killed Thursday in clashes between Zaidi Shiite rebels and Sunni Salafists in northern Yemen, a security official said.

Clashes erupted in the morning in the northwestern Hajjah province between rebel gunmen, known as Huthis, and Sunni extremists, the local official told Agence France Presse.

Palestinian President Mahmoud Abbas will on Sunday begin a week-long European tour to Britain, Germany and Russia, his spokesman said on Thursday.

"Abbas will go on Sunday to London, and meet with Prime Minister David Cameron and other British officials on Monday and will brief them on the latest political developments in the region," Nabil Abu Rudeina to Agence France Presse.

Syrian security forces on Thursday shot dead 32 people across the country, activists said, as a rights group said troops opened fire on anti-regime protesters as they tried to approach Arab League monitors in the country’s northwest.

The Local Coordination Committees, the main activist group spurring protests on the ground, said security forces killed 30 civilians and two army deserters in several regions.

Thousands of Yemenis demonstrated on Thursday in several cities voicing their rejection of a Gulf Arab deal to grant President Ali Abdullah Saleh immunity from prosecution, witnesses said.

In the capital Sanaa, protesters marched from Change Square, the focal point of almost a year of anti-Saleh demonstrations, through al-Siteen Street, an Agence France Presse correspondent reported.

Pakistan's President Asif Ali Zardari was in Dubai Thursday for a brief scheduled visit, an aide said, against a backdrop of mounting tension as the government faces new challenges to its rule.

The one-day trip came after a confrontation between Pakistan's civilian leaders and the military over a probe into the government's role in a scandal centered on a mysterious memo that sought US help in curbing the army's power.

A rocket was fired from the Gaza Strip into Israel on Thursday morning and hit without causing any damage or injuries, an Israeli police spokesman said.

"A rocket fired from the Gaza Strip exploded in the Sdot Negev region without causing any injuries or damage," he told Agence France Presse.