Fighting across Afghanistan killed 10 suspected rebels, six police and five medical workers, and President Hamid Karzai (search) said Wednesday he believes the insurgents are receiving support from the nation's booming drug trade.

The suspected Taliban (search) guerrillas were killed Monday by U.S. warplanes that bombed their hideout in Uruzgan province, which has long been a hotbed of militant activity, local Gov. Jan Mohammed Khan (search) said Wednesday.

U.S. military spokeswoman Sgt. Marina Evans (search) confirmed the attack and said "several of the enemy had been killed."

The six police were killed by suspected Taliban who ambushed their convoy in the same area a day later, Khan said. One officer was still missing after the attack and feared dead. Reinforcements have been rushed to the area "to hunt down the Taliban," he said.

The attack on the medical workers happened Wednesday near Kandahar city, a former Taliban stronghold, said doctor Abdul Qadir, director of U.N. and U.S.-sponsored Afghan Help Development Services, a local aid group that employed the five.

Gunmen opened fire on their vehicle as they drove through the desert. Two of the five dead were doctors. Three other medical workers in the vehicle were wounded, Qadir said. The eight were returning to Kandahar after treating refugees in a nearby camp.

Karzai made his comments about the violence in a press conference with Secretary of State Condoleezza Rice (search).

When asked about an attack on police in southern Helmand province Tuesday that left at least 19 officers dead, he said there was "cooperation between the drug trade and terrorism." He said the region was well known as a center for trafficking opium and heroin.

Afghanistan produces an estimated 87 percent of the world's supply of both the drugs, sparking warnings that the country is becoming a "narco-state" four years after a U.S.-led invasion drove the Taliban from power.

"We will have terrorism attacking (us) ... for quite some time," Karzai warned.

He went on to say that fighting drugs was essential. "If we fail, we will fail as a state eventually and we will fall back in the hands of terrorism," he said.

Karzai's U.S.-backed government is struggling to strengthen Afghanistan's fragile democracy while dealing with a stubborn rebellion that has left about 1,400 dead in the past half-year.

Rice said the 21,000-strong U.S.-led coalition was doing its best to quash the insurgency.

"We are doing everything we can to defeat the terrorists. We cannot simply defend ourselves, we have to be on the offensive," she said.

There had been hopes that the U.S. military may have been able to reduce its number of troops here next year as a separate NATO-led peacekeeping force takes responsibility for security in volatile regions.

But Rice said U.S. forces will remain "for as long as they are needed in whatever numbers they are needed to make certain that they defeat the terrorists and Afghanistan becomes a place of stability and progress."

Meanwhile, four rockets exploded in Kabul just hours before Rice arrived. One hit a large compound housing the government's intelligence service, but there were no casualties. The other detonated outside the Canadian Ambassador's residence, wounding two guards, police said. The other two hit the outskirts of the city.

Fighting erupted in northern Afghanistan between two rival militia factions, wounding 10 people, officials said. Though the government and international community have spent millions of dollars disarming militias, several have retained their weapons and are seen as a further threat to this country's future.