March 2 (Bloomberg) -- An American diplomat was among four people killed today in a car bombing near the U.S. Consulate in Pakistan's southern port city of Karachi, two days before U.S. President George W. Bush visits the country.

``We have lost at least one U.S. citizen in the bombing, a Foreign Service officer, and I send our country's deepest condolences to that person's loved ones and family,'' Bush said in New Delhi during a tour of South Asia. ``Terrorists and killers are not going to prevent me from going to Pakistan.''

Pakistan has had dozens of attacks in recent years, many of them in Karachi. The U.S. Consulate in the city has been among the targets. President Pervez Musharraf blames the violence on opponents of his support for the U.S.-led campaign against terrorism. Some of the attacks are attributed to rivalries between the Shiite Muslim minority and the Sunni Muslim majority.

A Pakistani employee of the consulate also died, Pakistan's Foreign Ministry said. About 50 people were injured, Javed Akbar, a police official in Karachi, said in a telephone interview.

``We are investigating the possibility of a suicide bomber exploding the vehicle outside the consulate,'' Akbar said. There may have been two blasts almost simultaneously, in a parking lot behind the U.S.-owned Marriott Hotel, at about 9:10 a.m. local time, he said.

Car Rammed

The bomber rammed the car into a vehicle carrying the U.S. diplomat, the Associated Press reported, citing an unidentified Pakistani security official. The spokeswoman for the U.S. Embassy in Islamabad, Nida Emmons, didn't immediately return calls seeking the diplomat's identity.

``It is premature,'' to say whether the U.S. Consulate was attacked by a suicide bomber, Information Minister Sheikh Rashid Ahmed told a news conference in Islamabad. The security officials are investigating the attack through pictures provided by security cameras installed outside the consulate and the Marriott, he said. Pakistan will take extra security measures for Bush's visit, he said.

There was no statement of responsibility for the attack, Karachi police chief Mushtaq Ahmad told reporters.

U.S. National Security Adviser Stephen Hadley, addressing reporters traveling with Bush in Delhi, said that initial security reports are often ``notoriously incomplete,'' but he added that ``there is some evidence'' the official may have been targeted.

``That is very troubling,'' Hadley said. ``It is a reminder we are at war.''

Previous Attacks

In 2002, 11 French engineers were killed in a bombing outside the Marriott, which is in a commercial center of Karachi. In November, three people were killed and 17 injured when a car bomb exploded in front of the PIDC office building in the same area of the city.

Gunmen killed two policemen in 2003 in an attack on the U.S. Consulate in Karachi, while a car bomb outside the consulate in July 2002 killed 12 people, including security staff. Two U.S. diplomats from the consulate died and a third was injured when gunmen fired on the van in which they were traveling in 1995.

Pakistan's government condemned today's attack, saying it ``illustrates the intentions of those who seek to harm our country and our ties with friendly nations,'' according to a Foreign Ministry statement.

Buildings, Cars Damaged

The bombings broke windows in nearby buildings, witness Fasial Khan, a real estate agent, said in a telephone interview. More than a dozen cars and motorcycles were destroyed, police said.

Pakistan's benchmark Karachi Stock Exchange 100 index fell 0.8 percent to 11,381.25 at the close on concerns over security.

``The bomb blast has subdued the sentiment of investors, who fear President Bush may cancel his visit,'' said Tanvir Abid, head of research at Live Securities Ltd. in Karachi.

Bush's visit to Pakistan will take him to the capital, Islamabad, about 1,000 miles (1,600 kilometers) north of Karachi. His comments today in neighboring India came during a news conference with Indian Prime Minister Manmohan Singh in which Bush said the two countries agreed to terms of an accord that would give India access to U.S. nuclear power technology.

As a sign of concern about the security situation in Pakistan, the White House announced only on Thursday that Bush would spend Friday night in Islamabad.

Typically, the president's entire itinerary is announced up to a week before he leaves Washington on a foreign trip; in this instance, White House officials told reporters that Bush would travel to Pakistan only during the day Saturday after spending three nights in India. The printed schedule they distributed only ran through Thursday.

Hadley, speaking to reporters in Delhi, said the decision to spend one night in Islamabad ``was made a while ago.''

``Obviously, because of the security situation, it was something we would like to announce as late as possible,'' Hadley said.

To contact the reporters on this story: Haris Zamir in Karachi at hzamir@bloomberg.net; Khalid Qayum in Islamabad at kqayum@bloomberg.net.

Last Updated: March 2, 2006 09:46 EST