RIYADH, Saudi Arabia — U.S. Vice President Dick Cheney arrived Saturday in Saudi Arabia for talks with King Abdullah, apparently seeking the Sunni royal family's influence and tribal connections to calm Iraq after an especially violent week.

The vice president's visit one day visit to the kingdom comes at a time of upheaval across the region and as regional diplomatic efforts to calm several potentially explosive situations have foundered.

In Iraq, the slaughter Thursday of 215 people in a series of car bombs by suspected Sunni insurgents in a Shiite neighborhood prompted a new political crisis ahead of talks scheduled for Wednesday and Thursday in Jordan between the Iraqi premier and U.S. President George. W. Bush.

A top Shiite political party that Iraqi Prime Minister Nouri al-Maliki depends on for power threatened to withdraw from the government if he meets Bush.

But developments in Iran, Lebanon and the Palestinian territories have heightened worries of further regional instability and are expected to be on the agenda of Cheney's talks with Abdullah.

Talks are also expected to treat Iran's nuclear program that the U.S. and some of its Western allies believe aims to produce an atomic weapon. Iran has denied the accusations.

Gulf countries are concerned about a neighbor obtaining nuclear capabilities, but also about any military attacks on Iran because several host U.S. forces and fear that they would be on the front line of any reprisals.

Iran's plans for a three-way summit that would have brought its leader and those of Iraq and Syria together Saturday collapsed after Iraq's main international airport was closed and Syria had failed to respond to the invitation.

Lebanon's political crisis deepened last week with the assassination of the Christian interior minister. The Shiite Hezbollah for weeks has been threatening mass demonstrations to bring down the government unless it and its allies get greater representation in Cabinet that would effectively give them veto power.

Meanwhile, efforts to broker a deal between the Palestinian Hamas and Israel for the return of an Israeli soldier captured by militants affiliated to Hamas, which leads the Palestinian government, have failed to achieve breakthroughs.

The U.S. veto of a recent draft resolution submitted to the United Nations Security Council criticizing Israel's shelling of a home in Gaza, killing at least 18 people, has fueled anger in the territories.

Saudi Arabia, as the wealthiest Arab country, is a key broker in the region and a staunch U.S. ally.

The vice president was not planning to make additional stops in the region.