Barack Obama, the US president, has said the military offensive currently under way against the Taliban in Afghanistan has "a long way to go".
"We knew this summer was going to be tough fighting ... we still have a long way to go," Obama told Britain's Sky News channel in an interview on Saturday.
The southern province of Helmand is the focus of the current operation where thousands of extra US marines have been brought in to drive out the Taliban fighters.
Marines are concentrated in the southern tip of Helmand province, around the districts of Garmsir, Khanashin and Nawa.
US special forces are also working with Afghan commandos around the Baramsha border crossing with Pakistan, in an attempt to cut off the Taliban's main supply route.
Taliban territory
Since the start of July, 36 foreign soldiers have died and the Taliban has said it has made gains.
Qari Yousef Ahmadi, a Taliban spokesman, told Al Jazeera: "We have been successful. The enemy has been suffering heavy casualties.
"It is a guerrilla war and those are our tactics. We will resist them in Helmand, and will attack them all over Afghanistan."
A high-ranking government source in Helmand told Al Jazeera that the offensive was proceeding slowly, and in central Helmand, the "enemy" was in fact much stronger.
Zeina Khodr, Al Jazeera's correspondent in Kabul, said: "The Taliban has been ambushing troops; they have been laying improvised explosive devices and roadside bombs. So, the [foreign forces'] advance really is slow."
"This is a guerilla war, it is not going to end soon and it is highly unlikely that the Taliban will give up territory such as Helmand, such a strategic area."
"A Taliban spokesman told us that the outcome of this operation 'would tell us who is actually the man, and who is the woman'," our correspondent said.
'Diplomacy and development'
President Obama said the US and its allies needed to combine their military efforts in Afghanistan with diplomacy and development "so that Afghans feel a greater stake and have a greater capacity to secure their country".
After Afghanistan's planned election next month, "we need to start directing our attention to how do we create an Afghan army? An Afghan police? How do we work with the Pakistanis effectively so that they are the ones who are at the forefront of controlling their own countries?" Obama said.
Al Jazeera's correspondent said this is something the Afghan officials have been saying for months, if not years.
"The US still needs to develop the Afghan security forces, and that will take some time."
"Government forces lost the district of Nuristan on Thursday because they didn't have enough local security forces," our correspondent said.
"The governor at 5am [0030GMT] this morning confirmed that they had regained that district from the Taliban, but holding it will be a difficult fight."
PHOTO CAPTION
Afghan children walking to school pass by U.S. (L) and French soldiers conducting a joint patrol with Afghan troops in the village of Hajian, in the mountains of Wardak Province in Afghanistan July 12, 2009.
Al-Jazeera