U.S. rockets on Monday erupted into a hotel in the Afghan capital of Kabul used by Taliban troops, leaving the street littered with the wreckage of a Taliban vehicle and pieces of bodies, residents told Reuters.

They heard what sounded like helicopters before the rockets slammed into the base just before dawn. That would mark a change in U.S. tactics from using high-flying jets in the dramatically escalating U.S. bombing campaign against the ruling Afghan militia's troop positions in the north.

B-52 bombers were seen high in the skies over Dashtequala Sunday and other planes could be heard over the area. Vibrations from the bombing runs shook the ground in nearby villages more than they have at any time since the attacks here began last Sunday.

Reporters saw at least nine carpet-bombing runs on Taliban positions along Kalakata Hill, with one plane dropping as many as 20 bombs. The bombs landed in rapid-fire succession, blowing black smoke high into the air.

Local commanders with the Northern Alliance said the U.S. planes appeared to be using a combination of conventional "dummy" bombs, so-called "bunker-busters" and the targeted carpet bombs throughout the day, in what was by far the heaviest U.S. bombing they have seen.

Along with more bombs, reporters and alliance officials on the scene saw more planes in action than ever before. There were five American planes visible to the naked eye at one point, with perhaps more flying out of sight at higher altitudes.

However many there were, the planes continued their frequent pounding through the morning and into the afternoon at Kalakata, a key strategic stronghold that overlooks the Kokcha River along the Afghan-Tajik border. Sunday's attacks followed a wave of less intense airstrikes that began on late Saturday afternoon, and represented the first back-to-back days of bombing in the area.

Northern Alliance spokesman Ashraf Nadeem said anti-Taliban forces launched a major attack Sunday in Balkh province, south of the strategic Taliban-held city of Mazar-e-Sharif, after U.S. jets pounded the area earlier in the day.

Nadeem said the attack was a joint operation involving ethnic Uzbek warlord Rashid Dostum, Atta Mohammed of the Jamiat-e-Islami faction and Shiite Muslims led by Mohammed Mohaqik.

The three were among alliance leaders who met last weekend to plan for a major assault on Mazar before the beginning of the Islamic holy month Ramadan this month and the advent of winter.

In Kabul, American bombs struck near the Intercontinental Hotel, set on a hill in the southwest part of the city. Nine people were injured, the Taliban news agency said. The report could not be independently confirmed, and it was unclear whether the injuries were in the hotel.

U.S. jets also struck the front line about 30 miles north of Kabul, Atiqullah Baryalai, deputy defense minister of the Northern Alliance, told the Associated Press by telephone. They also hit the northeast town of Taloqan, which the opposition lost to the Taliban last year.

Along the Kabul front, opposition tanks and soldiers conducted military exercises ahead of a possible offensive in that area.

There were no official reports of casualties in Sunday's attacks. International aid agencies in the Afghan capital of Kabul, however, said hundreds of injured soldiers have been taken to hospitals there.

The attacks were taking a heavy toll on Taliban soldiers and supplies, according to the first eyewitness accounts of people who have fled the area.

"The Taliban are in bad condition, that's for sure," said Mohammed Ursal, who spoke to Fox News after reaching a river crossing in Northern Alliance territory over the weekend. "I saw myself that there were a lot of them killed and injured in the attacks."

Rasul and his family were the first group of refugees from the strategic town of Taleqan to reach safety since the U.S. stepped up the pace of attacks at the end of last week. Rasal said he and his family of four had spent two days making the 25-mile trek out, traveling by foot and then by donkey over what he called "secret passes" not patrolled by the Taliban.

Taleqan is located on a major east-west road that runs through the cities of Kunduz and Mazar-e-Sharif, considered by many here to be the new focus of the Taliban-alliance conflict. Fierce fighting was reported around Mazar by both sides in recent days, with the Taliban claiming they had repulsed a major attack east of the city.

Capturing Mazar-e-Sharif from the Taliban would clear a supply route for the Northern Alliance, enabling them to bring in weapons and equipment from neighboring Tajikistan and Uzbekistan.

Rasul and others fleeing the area said the repeated U.S. strikes had hit a number of key military targets, including fuel and ammunition dumps and transport vehicles. Eyewitnesses said they did not see any civilian targets hit in the attacks.

By Saturday evening, a crowd of refugees fleeing the bombing in Taleqan gathered at a river crossing on the Kokcha, anxious to reach the relative safety of alliance positions on the other side. The river crossing was just out of reach of Taliban heavy artillery in the nearby hills, local commanders said.

Despite the increased U.S. strikes, there is still no sign of any alliance offensive against frontline Taliban positions. Local commanders said in repeated interviews over the weekend they were patiently waiting for word of an advance from their Defense Ministry.

Some local commanders, who are part of a rather loosely organized chain of command in the alliance military, have said they are eager to press on with an anti-Taliban offensive before the onset of winter. Others, however, have suggested they would rather wait for spring, and rely on U.S. bombing through the winter to further weaken Taliban positions.

Several alliance commanders have also said they do not expect a major offensive any time soon against frontline Taliban positions in the Panshjir Valley, north of Kabul. Mountain passes in the region are already closing up for the winter and may trap thousands of soldiers and journalists there who might try to leave.

The ferocity of Sunday's attacks suggested to many that U.S. Special Forces must now be in the area of northern Afghanistan, helping target the precise bombing runs. The areas hardest hit in recent days have been just across a hillside from alliance frontline positions.

U.S. officials have conceded that Special Forces are in operation around the area of Mazar-e-Sharif, but have not commented on their potential presence in northern Afghanistan. There is no question, however, that the area is of much greater interest to American military commanders.

The Associated Press contributed to this report