KABUL, Afghanistan -- As the Afghan war's bloodiest month for Western forces drew to a close Wednesday, the widening scope and relentless tempo of battlefield casualties pointed to a formidable challenge for U.S. Army Gen. David Petraeus, the incoming commander.

At least 102 coalition troops were killed in June in Afghanistan, according to the independent website icasualties.org, far surpassing the previous monthly record of 77 military fatalities in August 2009.

In a reflection of the increasingly American face of the war as the summer's troop surge presses ahead, at least 60 of those killed were U.S. service members, including a soldier killed by small-arms fire Wednesday in eastern Afghanistan.

Buried bombs, or improvised explosive devices, continued to cause the most fatalities, despite what the military had described as some success using electronic surveillance to spot insurgents planting bombs and to stage raids on IED-producing rings.

But other hazards have pushed to the fore as Petraeus, who was confirmed Wednesday by the Senate 99-0, takes command in Afghanistan.

Firefights, helicopter crashes, ambushes, sniper fire and complex coordinated assaults -- such as Wednesday's failed attempt by insurgents to fight their way onto NATO's largest airbase in eastern Afghanistan -- also exacted a significant toll in deaths and injuries.

As the pattern of fatalities shows, it is a war with a widening geographical reach. The country's east and south, the traditional Taliban strongholds, predictably saw the heaviest fighting, but a swath of the north became increasingly restive as well.

A day in which a military death does not occur somewhere in Afghanistan has become rare. And fatalities taking place in clusters of four or more in a single incident have become increasingly common.

In a far-flung country with relatively few passable roads, NATO's war effort relies heavily on helicopters. Two of them crashed in June, killing eight troops. One of the choppers was shot down by Taliban fighters, a formerly rare feat but a capability that may be assuming a more prominent place in the insurgents' arsenal.

Petraeus acknowledged that battlefield casualties were unlikely to decline much as the summer wore on. "My sense is that the tough fighting will continue," he said Tuesday at his confirmation hearing. "Indeed, it may get more intense in the next few months."

U.S. military officials in Afghanistan attribute the heightened fatalities to the growing numbers of troops, combined with "going into places we haven't been, just a generalized increase in our operations," said Col. Wayne Shanks, a spokesman for NATO's International Security Assistance Force.

Afghan forces too have been seeing larger numbers of troops killed. The Afghan army lost 37 men in June, said a Defense Ministry spokesman.

The insurgents' growing boldness -- and willingness to sacrifice foot soldiers to stage an attention-getting attack with little hope of success -- was reflected in Wednesday's strike on U.S.-run Jalalabad airfield.

The attack also echoed strikes in the past five weeks on similarly large and well-fortified installations, Bagram airfield, north of Kabul, and Kandahar airfield, in the south. In both cases, the insurgents also failed to penetrate the bases' perimeters.