AT the sound of the explosions, traffic stops, heads turn, and the driver freezes in his seat. When it became clear a truck has backfired twice, he sighs.
''I thought we were under fire,'' says Khan, an unemployed electrical engineer working as a taxi driver. ''Every day, 10 or 20 people die in Karachi. The government has the power, but they don't do anything. Why?''
As Pakistani Prime Minister Benazir Bhutto wraps up a crucial one-week tour of the United States culminating in a meeting with President Clinton tomorrow, Karachi, the country's commercial capital, is in turmoil.
Pakistan's largest city, where two US consulate workers were murdered in an apparent terrorist attack last month, has become a cauldron of the forces development officials have long warned could beset overcrowded cities in developing countries. Approximately 20 to 30 percent of Karachi's 12 million people are believed to be unemployed, living in extreme poverty, and have no running water or electricity.
Nearly 1,000 people were killed here last year, and more than 350 have died already this year in violence that ranged from clashes between religious groups, to feuds between drug kingpins, to petty crime. Murders in Karachi, the vast majority of which are never solved, have become so common and their motives so convoluted that it's unclear who is killing whom or why.
With sectarian violence growing, some observers warn Karachi has become a fertile recruiting ground for Islamic fundamentalist groups. In interviews, residents expressed deep frustration with Ms. Bhutto's government for not doing more to end the violence, and most also express deep disdain for all of Pakistan's political parties.
''I don't trust any of them,'' says Ishmael Mohammed, a photography-store owner.
''Politics is all corruption, they're all 100-percent corrupt,'' he says in disgust.
Karachi is the most glaring reminder of the reforms that Bhutto must begin when she returns from the US, according to Pakistani and Western observers.
''The unemployment problem is there, the social-inequality problem is there, the population is growing every day, there is a shortage of water, there is a shortage of hospitals, we know it,'' says A. Q. Khalil, senior vice president of the Karachi Chamber of Commerce and Industry.
''We are asking the government to sit down with the local authorities and solve the problems,'' Mr. Khalil adds.
A militant organization
Since she regained power in 1993, Bhutto has been battling with the Mohajir Quami Movement. The MQM is a militant organization that represents Indian Muslims, or Mohajirs, who came to Pakistan when the subcontinent was divided in 1947.
The group, which enjoys widespread political support from Karachi's 80 percent Mohajir majority, has been demanding that local elections be held.
The MQM won control of the municipal government in 1987 but was thrown out by federal government authorities due to alleged corruption.
The Pakistani military policed the city for a year and a half during 1991 and 1992, but were largely unsuccessful in seizing weapons from the city's various religious and political factions -- including the well-armed MQM. More than 100,000 privately owned AK-47s, remnants of US supplies to Afghan fighters during the Soviet occupation, are still believed to be in the city.
Bhutto has refused to negotiate with the group, maintaining they do not enjoy widespread support in the city and also rejected holding new elections, to the dismay of some Western diplomats.
''You've effectively said, 'No, we're not going to have elections down there because your people won't win','' says a Western diplomat based in Islamabad referring to Bhutto's intransigence on the topic.
''Anyone would say that the solution down there has got to be political,'' he adds.
Residents also express a deep resentment against the city's police force, which has stood by while clashes between Karachi's well-armed factions have occurred. They also said widening social inequalities are also exacerbating tensions.
The city's contrasts are striking. In one part of Karachi, industrialists treat their families to ornate banquets in five-star hotels. Women in elaborate silk saris stroll through the hotel's Western shops as a Pakistani policeman armed with a submachine gun stands guard.
A few blocks away, a dead goat rots on the sidewalk and beggars use a nearby narrow alley as their toilet.
Pakistani observers say Bhutto must also do something to alleviate the city's social inequalities.
''The wealth displayed here and across this country is obscene,'' says Dorab Patel, a former Supreme Court justice in Pakistan and a founder of the Pakistani Human Rights Commission. ''I don't blame the young men for trying to steal it.''
Bhutto is also under intense pressure to deliver concrete changes in US policy toward Pakistan. A general strike was called by the Pakistani Chamber of Commerce during first lady Hillary Clinton's visit to Islamabad last month to demand action from Bhutto in Karachi.
The Western-educated prime minister is pressing for an end of the Pressler Amendment, passed in 1990, during her visit to the US. It is the first by a Pakistani leader in five years.
The amendment froze US aid to Pakistan to punish the government for failing to abandon its nuclear-weapons development program. Bhutto has maintained that Pakistan will continue its program as long as its rival India does and the Clinton administration is urging Congress to revoke or water down the amendment.
High hopes for visit
Pakistan's politically powerful military is also hoping F-16 fighter jets paid for by Pakistan worth $1 billion but withheld by the US since the amendment was enacted will finally be released. Business leaders say they have signed foreign-investment agreements worth $6 billion, but the amendment is blocking US investment in Pakistan from actually occurring.
''We have many hopes with this visit,'' says Mr. Khalil of the Karachi Chamber of Commerce and Industry. ''We have signed many agreements in the past. Whether anything is enacted is the key.''
Western diplomats warn that Bhutto, who says foreign investment is a key tool in developing the economy and stabilizing Karachi, must deliver.
''This trip is extremely important because of the expectations that have been raised,'' says the Western diplomat. ''It's been the only thing in the news here.''
But according to Khan, the unemployed engineer who did not give his last name, the key to solving the problem is Bhutto's government. ''If America gave us $20 million for jobs,'' he says, ''90 percent of the money would go in the politicians' pockets.''