ISLAMABAD, Pakistan — When President Clinton visited Pakistan six years ago, he said much was wrong in the impoverished Islamic nation: It wasn't democratic enough. Terrorism was a problem. And money was squandered building a nuclear bomb.

No doubt friendlier words will be spoken on Saturday during President Bush's first visit to Islamabad. Pakistan has become a key ally in the war on terror, and Washington has offered to sell the country F-16 fighter jets.

But all is not well with Pakistan and its relations with the United States.

Anti-U.S. sentiments run deep among its 150 million people, and the threat of terrorist attacks hasn't faded. An apparent suicide bombing Thursday near the U.S. Consulate in Karachi killed four people, including an American diplomat.

Pakistan is also in the throes of anti-Western protests against Prophet Muhammad cartoons that have left at least five people dead. On Friday, police swung batons to disperse about 1,000 demonstrators chanting "killer go back" and "death to America" and trampling on the American flag. The protest was in Rawalpindi, a city about four miles from where Bush's plane was expected to land.

Security will probably be as tight as it gets. When Clinton visited in 2000, he made a last-minute plane switch before he took off for Pakistan from neighboring India. He arrived in an unmarked Gulfstream jet, which landed five minutes after a USA-marked decoy plane touched down.

Extraordinary security measures are still warranted here because the shadow of al-Qaida and the Taliban continues to hang heavy over Pakistan.

Although Pakistan has arrested more than 700 al-Qaida suspects in the past four years, including the masterminds of the Sept. 11 attacks, key terror leaders are still thought to be at large within its borders.

Bush's visit might bring him closer than he's ever been to Osama bin Laden, believed to be in hiding along the rugged border with Afghanistan.

Less than two months ago, the United States thought al-Qaida's No. 2 leader, Ayman al-Zawahri, was attending a dinner party in a northwestern region near the Afghan border. A U.S. missile strike on the village missed al-Zawahri, who apparently wasn't there, and killed 13 residents, including women and children.

The attack enraged Pakistanis and set off protests by Islamic moderates as well as radicals — a rare show of unity between groups that have played a tug of war over the country's identity since its birth during partition from India after independence from Britain.

Pakistan's military leader, President Gen. Pervez Musharraf, insists most Pakistanis are moderates. He often complains his nation is viewed to be a hotbed of extremism and says his goal is to puncture the misconception.

But his crackdown on radicals has drawn criticism from moderates and human rights groups, as has his tough military action against suspected terrorists. This week, the army said an airstrike on a border village killed 45 militants at a suspected al-Qaida hideout.

Musharraf seized power in a bloodless coup in 1999, and this was a major point of contention with Clinton, the first American president to visit Pakistan since 1969.

Clinton urged Musharraf to make a plan to return to civilian rule. The Pakistani leader later pledged to relinquish his military post by the end of 2004, but he has reneged on that promise. He says the nation still needs the military's firm hand.

Bush recently acknowledged that Pakistan still has "distance to travel on the road of democracy." But he has also lavished praise on Musharraf, calling him a brave warrior in the war on terror.

That praise could be tempered by concerns over militant infiltration from Pakistan into Afghanistan, where U.S. forces have come under increasing attack in the past year.

Before the Sept. 11 attacks, Pakistan was one of only three countries that recognized Afghanistan's former Taliban regime, but it switched allegiance before the U.S.-led war across the border.

The war on terror was a blessing for Pakistan in many ways. It helped pull the country out of the international isolation it suffered after Musharraf's coup and its nuclear tests in 1998. Clinton criticized Pakistan's push to join the nuclear club and urged the country to end its arms race with rival India. The neighbors have fought three wars since independence.

But after Bush announced a landmark deal in New Delhi Thursday to share American civilian nuclear know-how and fuel with India — which like Pakistan had faced U.S. sanctions for conducting nuclear tests in 1998 — Pakistan will be vying for similar cooperation.

That's unlikely, considering that just two years ago Pakistan's leading nuclear scientist, A.Q. Khan, was exposed as the chief of a lucrative black market in weapons technology that had supplied Iran, Libya and North Korea. The government denied any knowledge of his proliferation activities.