Updated

Saudi Arabia (search)'s U.S. ambassador warned Monday that intelligence suggests there could be more terror attacks in Saudi Arabia or the United States, while an American official said Al Qaeda has a presence in the royal kingdom.

Prince Bandar bin Sultan (search) also said the kingdom received warning before the May 12 bombings that killed 34 people, including eight Americans, at three housing compounds outside of Riyadh (search), the Saudi capital.

"Yes, we had warning, yes we had heightened alert but we never had a specific time and place designated," Prince Bandar told reporters in Riyadh.

Other attacks were possible, he said, based on new intelligence.

"There is chatter, a high level of chatter regionally and in other international spots" about possible attacks in Saudi Arabia or the United States, Prince Bandar said.

The FBI warned Monday that Al Qaeda could mount new attacks in the United States as well as target American and Western interests overseas.

Other U.S. officials said Monday that Saudi and U.S. investigators are fully cooperating in the probe into the Riyadh attacks, though an FBI team is not interrogating suspects.

Meanwhile, a man standing with a gun outside the U.S. Consulate in Dhahran, 300 miles east of Riyadh, was arrested Monday and was being questioned by Saudi police, a U.S. Embassy official said.

U.S. diplomats said no one was injured or threatened in the incident, but that the consulate was closed until further notice. In 1996, a truck bombing killed 19 Americans at the Khobar Towers barracks near Dhahran.

A U.S. official said Monday that Al Qaeda has some presence in the royal kingdom.

"We don't believe there are tens of thousands of Al Qaeda members in Saudi Arabia but we believe the Al Qaeda presence is more than a single cell or two," the official in Riyadh said on condition of anonymity.

On Sunday, Saudi Interior Minister Prince Nayef said authorities have arrested four suspects apparently linked to Usama bin Laden's terrorist network over the car bombings. Asked whether the four men in custody belonged to Al Qaeda, Nayef said, "All indications point to that."

Nayef's comments were the strongest sign yet that bin Laden's terrorists -- who have carried out deadly strikes from Nairobi, Kenya, to New York -- may have played a part in the bombings in the Saudi capital.

But Prince Bandar, who is known for handling some of his country's most delicate diplomatic tasks, told reporters after returning to Saudi Arabia from Washington that Saudi authorities had obtained information during recent months that Al Qaeda had been wracked by internal divisions.

Saudi officials believed that Al Qaeda leaders were so split that they didn't want to risk carrying out any attacks in Saudi Arabia, which is bin Laden's birthplace, in order to maintain their intellectual base within the Gulf kingdom.

"[But] they have mended their differences and decided to come out," said Prince Bandar, who is known for his close relations with the U.S. administration.

The prince downplayed press reports that officers within the Saudi National Guard had supplied a 19-member Al Qaeda terrorist cell with a recently seized cache of guns and explosives.

He said the weapons and explosives had instead fallen into the terrorist cell's hands after being brought into Saudi Arabia from neighboring Yemen, another hotbed of Islamic fundamentalism.

The Saudi government had said the 19 were believed to be receiving orders directly from bin Laden and had been planning to use the seized weapons to attack the Saudi royal family and American and British interests.

Prince Bandar said the 19 men are believed to have been "the major cell in Saudi Arabia [aiming] to do bad things." Two of the cell were believed to be very senior Al Qaeda members because their names kept popping, including in February during the Islamic pilgrimage -- or hajj -- to Saudi Arabia when a heightended terror security alert was posted in the kingdom.

A U.S. official said Saudi investigators were "being totally cooperative." Both sides have been saying they expect better coordination compared to the investigation into the Khobar Towers bombings, when U.S. officials complained about being denied access to evidence, witnesses and suspects.

More than 60 FBI and other U.S. investigators are assisting Saudi authorities with the probe into Monday's attacks.

"We're getting real and good cooperation," the U.S. official in Riyadh said Monday. He said reports that Saudi authorities were obstructing the investigation were "100 percent false."