The officials said police went to a Bedouin village searching for a fugitive, and tribesmen opened fire on them. No one was hurt in the shootout, or in the subsequent Bedouin attack on the convoy, setting three vehicles ablaze.

The officials spoke on condition of anonymity because they were not authorized to speak to reporters. They gave no further details.

Sinai's impoverished Bedouins complain of mistreatment by the Egyptian government. Many make their living smuggling weapons, drugs and people into Israel. A three-year blockade of Gaza by Egypt and Israel, aimed at Gaza's militant Islamic Hamas rulers, led to a lucrative smuggling industry, using dozens of tunnels dug under the 9-mile (15-kilometer)-long border between Gaza and Egypt.

After a bloody May 31 confrontation at sea between Israeli naval commandos and pro-Palestinian activists trying to sail to Gaza, Israel pledged to lift its civilian blockade on Gaza, banning only weapons and items that can be used for military purposes.

In parallel, Egypt partially opened its border crossing to let thousands of Palestinians in and out of Gaza.

The loosening of the blockade could affect the livelihood of the Bedouin smugglers, possibly leading to violence like Sunday's attack on the Gaza-bound convoy.

Later Sunday, Bedouins later tried to blow up a natural gas pipeline about six miles (10 kilometers) south of El-Arish in northern Sinai, close to the Gaza-Egypt border.

The blast caused slight damage to the pipeline but not leak, the officials said. An unexploded mortar shell was found near the pipeline.