Shelling in Yemen's capital killed five supporters of a powerful chieftain on Tuesday, his tribe said, as clashes intensified between embattled President Ali Abdullah Saleh's security forces and tribesmen seeking his ouster.

In the second successive day of fighting, a source close to tribal chief Sheikh Sadiq al-Ahmar told Agence France Presse that "an armored vehicle stationed near the interior ministry fired shells and killed five people" outside his home.

President Barack Obama is a "pawn" who cannot save Israel, Iranian President Mahmoud Ahmadinejad said on Tuesday, in a speech broadcast live on state television.

"You are a pawn who has been given a mission to save American and the Zionist regime but of course you won't be able to do it," Ahmadinejad said, addressing the U.S. president.

Libya's rebels have accepted an invitation to open a representative office in Washington, top United States official Jeffrey Feltman said on Tuesday.

"I delivered a formal invitation to the council for the opening of a representation in Washington," Feltman told a news conference, referring to the rebels' National Transitional Council.

Palestinian authorities do not intend to declare unilateral independence, a top Fatah member said Tuesday following talks with senior Russian officials.

"We do not intend to unilaterally declare independence," Fatah member Azzam al-Ahmed said one day after meeting Russian Foreign Minister Sergei Lavrov.

Palestinian Prime Minister Salam Fayyad was recovering from a procedure in hospital Tuesday after suffering heart trouble during a private U.S. visit, his office said.

Fayyad was taken to the Seton Medical Center in Austin, Texas on Sunday after complaining of "severe pains in the chest," the premier's office in Ramallah said in a statement.

Powerful explosions rocked Tripoli Tuesday as NATO launched its heaviest bombardment yet of the capital, while France and Britain piled pressure on Moammar Gadhafi by bringing attack helicopters into the Libya fray.

Government spokesman Moussa Ibrahim told reporters that at least three people died and 150 were wounded in the air strikes, which he said targeted a deserted military barracks but which instead hit civilians living nearby.

An accidental blast at Iran's Abadan's oil refinery killed at least one person and injured more than 20 during a visit Tuesday by President Mahmoud Ahmadinejad, who was not affected and went on to make a televised speech, reports said.

"A technical fault led to an explosion in one of the units of this refinery," Fars news agency said, referring to the oil facility in the southwestern city of Abadan.

Israeli Prime Minister Benjamin Netanyahu Monday vowed that the Jewish state would never withdraw to the "indefensible" 1967 border, revisiting a spat over the issue with U.S. President Barack Obama.

Netanyahu told the powerful pro-Israel lobby said he would spell out his vision for peace with the Palestinians in a speech to Congress on Tuesday, but promised that would not include a withdrawal to lines that existed before the 1967 Six Day War.

Six people were killed and dozens wounded during armed clashes in Sanaa on Monday between police and supporters of powerful opposition tribal chief Sadiq al-Ahmar, tribal sources and state media said.

The clashes came a day after President Ali Abdullah Saleh refused to ink an accord brokered by the Gulf Cooperation Council (GCC) under which he would cede power within 30 days in exchange for immunity from prosecution for himself and his aides.

The European Union, welcoming U.S. President Barack Obama's Middle East policy shift, Monday called for an "early meeting" of the Quartet group of world powers seeking an Israeli-Palestinian peace deal.

It also welcomed the recent reconciliation between rival Palestinian leaders from Fatah and Hamas and reiterated readiness to recognize a Palestinian state "when appropriate".