Mecca, Saudi Arabia ? Police fought overnight gunbattles with suspected al-Qaida militants who were planning an imminent terrorist attack, killing five and arresting others believed linked to last month’s suicide bombings in Riyadh, Saudi officials said Sunday.

One security official, speaking on condition of anonymity, said two police officers were killed in a shootout at a checkpoint shortly before a fierce gunbattle erupted during a raid on a bomb-filled, booby-trapped apartment late Saturday.

A Saudi Interior Ministry statement said the raid took place at an apartment building in the al-Khalidiya district, about three miles from the main Mecca mosque, at 9:30 p.m.

The statement said police clashed with a “group of terrorists…(who) were preparing an imminent terrorist act.” No details of the alleged plot were given.

Five suspected militants died in the gunbattle initiated by the “terrorists,” the statement said without giving their nationalities. Five security agents and four bystanders were slightly injured.

The statement said the apartment was booby-trapped and ready to explode. Some 72 bombs of different sizes were found with numerous other weapons, including semiautomatic rifles and knives, communication devices, bomb-making materials and masks.

The Interior Ministry statement said two Chadians, an Egyptian and a Saudi were among at least five people arrested in the raid. The fifth was not identified. Numerous other suspects were arrested later in Mecca. It did not elaborate.

The official told The Associated Press that he believed the suspected militants were “members of al-Qaida cells” because of similarities between weapons they used and how they “immediately shoot at the police when cornered.”

He also believed those killed and arrested were connected to the May 12 suicide bombings on Western residential compounds in the Riyadh that killed 35 people, including nine Americans and nine Saudi suicide bombers. He did not elaborate.

The official said the suspects were planning to carry out attacks in Mecca, Islam’s holiest city, according to information gathered during interrogations Sunday. He did not identify any intended targets.

The official said Saturday’s violence started when police manning a checkpoint tried to stop a car carrying the militants, who fired on the police, killing two of them, before fleeing to the al-Khalidiya apartment building.

The holy city of Mecca, located some 450 miles west of Riyadh, welcomes millions of Muslim pilgrims each year. The city is the birthplace of Islam’s seventh-century prophet, Muhammad.

Saudi authorities have cracked down on suspected militants since the May 12 bombings, which were seen as attacks not just against foreigners but also the ruling Saudi royal family for its close ties to the United States.

U.S. and Saudi investigators have been jointly probing the Riyadh bombings, which have been linked to al-Qaida, the Muslim terror network blamed for the Sept. 11, 2001, attacks on America.

Saudi’s interior minister Saturday said at least 30 people have been identified as being linked to the bombings, including people currently in custody and those who died during or following the attacks. It is unclear how many people have been arrested.

On May 31, Yosif Salih Fahd Ala’yeeri was killed in a gunfight with police in the northern Saudi city of Hael. Ala’yeeri was allegedly carrying a letter written by al-Qaida chief Osama bin Laden.

Ala’yeeri was among 19 al-Qaida operatives wanted following the May 6 discovery of a Riyadh weapons cache. The group was said to be taking orders directly from bin Laden and linked to the May 12 bombings.

Earlier this month, Saudi authorities had announced the arrests of numerous people in Medina, 540 miles west of the capital.

Security was unusually tight Sunday, with troops searching cars at checkpoints on Mecca’s outskirts and throughout the city. Police also patrolled inside and outside Mecca’s Al-Nur hospital, where those wounded Saturday were taken.

Abdul Khaliq Raheem Sheik, a 50-year-old Indian driver being treated for cuts, said three masked men holding guns had approached him earlier Saturday as he washed his employer’s car in al-Khalidiya.

Sheik said the men demanded he drive them from the area. When he refused, they shot the car’s windows and he was injured by flying glass.

The three then drove away, leaving Sheik behind. It was unclear if they were being sought or had been already killed or arrested.