Pakistani Prime Minister designate Shaukat Aziz (search) survived an apparent homicide bomb attack on his motorcade Friday that killed at least four people and injured two dozen, police and other officials said.

The attack came the same day the government announced the arrest of a senior Al Qaeda (search) operative on the FBI's most wanted list.

Suspicion in the blast fell immediately on Islamic militants, angry over the government's decision to back the U.S.-led war on terrorism.

In December, there were two failed attempts to assassinate President Gen. Pervez Musharraf (search), who blamed Al Qaeda for the bombings. On Thursday, the government acknowledged that it has held talks with Saudi officials about sending troops to Iraq as part of a Muslim peacekeeping force.

The bombing occurred at about 7:20 p.m. as Aziz, the finance minister who has already been tapped to take over as prime minister, was traveling through a bazaar in Fateh Jang, a town 35 miles southwest of the capital, Islamabad, said Mohammed Haidar, a local police official.

A man approached Aziz's car on foot on the busy street and then the blast went off, a senator from Aziz's ruling party said he was told by the prime minister-designate afterward.

"I spoke with Shaukat Aziz. ... His driver and a suicide attacker were killed," Sen. Mushaid Hussain, of the Pakistan Muslim League-Q party, told The Associated Press. "He (Aziz) was calm, cool and composed."

An Interior Ministry spokesman said at least four people were killed and two dozen injured in the attack. Geo Television reported six dead and 25 injured.

Mohammed Hassan, a senior Aziz aide, said the 60-year-old politician was safe. Another source close to Aziz told The Associated Press on condition of anonymity that the politician had returned to his home in the capital, Islamabad.

Aziz, a former Citibank executive credited with turning around Pakistan's economy under Musharraf, was in Fateh Jang to campaign for an upcoming by-election in an effort to win a seat in the lower house.

Musharraf's ruling party has said they want him to be prime minister, but the senator must first gain a seat in the Aug. 18 vote to be eligible. A victory is all but assured.

Opposition parties have denounced the proceedings as an affront to Pakistani democracy, five years after Musharraf seized power in a bloodless coup.

After Prime Minister Zafarullah Khan Jamali stepped down last month, Chaudry Shujaat Hussain was appointed caretaker prime minister while the political machinations are completed to allow Aziz to step in.

The attack followed the announcement early Friday that Pakistan had arrested Ahmed Khalfan Ghailani (search), a Tanzanian on the FBI's most wanted list who is wanted in the 1998 twin embassy bombings in East Africa.

Hussain said there was no evidence that the two were linked.

The attack also follows two attempts by Islamic militants in December 2003 to assassinate Musharraf, the ultimate powerbroker in this conservative Islamic nation of 150 million people. The second attack was close enough to kill several members of his entourage and more than a dozen passers-by.