KABUL, Afghanistan – Afghan leaders celebrated Independence Day on Monday with a small ceremony inside a fortified military compound, in marked contrast to the parade and public festivities a year ago and another sign that Taliban militants are bearing down on the government.

The top U.S. general in the country issued a rare public warning that militants planned to attack civilian, military and government targets. Only hours earlier, a suicide bomber killed 10 Afghans outside a U.S. base.

The unusual warning by Maj. Gen. Jeffrey J. Schloesser said “credible intelligence” indicated militants planned to launch attacks during Monday's celebrations, which were held both in the capital Kabul and around the country. But by nightfall, there had not been any attacks in Kabul where the main ceremony was held.

Kabul so far has been spared the spike in violence from a resurgent Taliban militancy afflicting much of Afghanistan. But there are signs the Taliban and other militant groups have gained a foothold in neighboring provinces and the capital suffered spectacular bomb attacks this year against an international hotel and the Indian Embassy.

A day before the 89th anniversary of Afghan independence from Britain, 7,000 police blanketed Kabul. Even the location of the official celebration was kept secret and remained closed to the public. Only about 100 people – diplomats and officials – attended the afternoon ceremony led by U.S.-backed President Hamid Karzai in the secure compound of the Afghan Defense Ministry. Karzai placed a bouquet of flowers on a monument in memory of fallen soldiers while a military band played the national anthem.

A year ago, Karzai oversaw a military parade and a colorful display of national dresses on the grounds of a Kabul stadium once used by the Taliban for public executions.

But this year, the celebration came only four months after gunmen in a hotel room fired on Karzai during a military parade in Kabul as he sat in the review stands. Karzai escaped injury, but the attack killed three people, including a lawmaker.

Authorities were trying to minimize the risk that insurgents could again disrupt a national commemoration.

A U.S. military statement said an increase in security and public awareness can “save Afghan lives, defeating the enemies' plan to discredit the Afghan government.”

While Afghan, U.S. and NATO intelligence officials say they often hear of and disrupt plans by militants, rarely does the U.S. go to such lengths to publicize the threat.

Two hours before the U.S. warning was issued, a suicide bomber detonated explosives outside an American base in the eastern province of Khost, killing 10 Afghan laborers and wounding 13, according to a U.S. military statement. Security forces stopped a second car bomber from detonating his explosives.

Officials said intelligence indicated a high threat level for the whole week.

All United Nations staff were ordered to work from home Monday as a precaution, said spokesman Aleem Siddique.

Taliban violence has spiked across Afghanistan in recent days, including an ambush on a NATO convoy on Sunday, attacks on police checkpoints and a roadside bomb targeting a police convoy. More than 90 people were killed over four days – most of them reportedly Taliban insurgents.

NATO said an insurgent attack killed a British soldier on patrol in southern Afghanistan Monday.

Overall, insurgent attacks jumped by 50 percent in the first half of 2008 from the previous year, according to data from the Afghanistan NGO Safety Office, a Kabul-based group that advises relief groups on security.

More than 3,400 people – mostly militants – have been killed in insurgency-related violence this year, according to an Associated Press count based on figures from Western and Afghan officials.