Afghan leader Hamid Karzai is meeting US President George W Bush amid renewed fears for the fate of 21 South Korean hostages still held by the Taleban.
US President George W Bush has told Afghan leader Hamid Karzai that he is proud to call him an ally, in a joint news conference near Washington.
Afghan security is the key issue in the leaders' two-day meeting at Camp David near Washington.
Mr Bush said 5m children - a third of them girls - were now going to school, while 340,000 Afghan people a month were receiving healthcare.
Two South Koreans from the abducted group have already been killed.
Thanking the US, Mr Karzai said 85,000 children aged under five were alive thanks to healthcare improvements.
Qari Yousaf, who claims to speak for the Taleban, said if there was no prisoner exchange, the hostages' fate would be the leaders' responsibility.
Mr Bush said: "Progress is being made, Mr President, and we're proud of you."
The Korean hostages - Christian aid workers, 18 of whom are women - were seized on 19 July as they travelled on a bus down the Kabul to Kandahar highway.
Afghan security is the key issue in the leaders' two-day meeting, as well as the booming trade in illegal drugs, the resurgent Taleban and civilian killings.
'Premature'
Mr Karzai said he had broached the subject of the growing number of civilians killed in coalition-led military operations in Afghanistan with the US leader.
Mr Yousaf said the Taleban had been told by South Korean negotiators that the South Korean president had asked Mr Bush to help with an exchange for Taleban prisoners.
He said: "I had a good discussion with President Bush on civilian casualties and I'm proud to tell you that President Bush felt very much with the Afghan people.
"We know that Karzai and Bush will discuss this. If the exchange doesn't take place the responsibility of the hostages will be that of Karzai and Bush," Mr Yousaf said.
"He called the Afghan people allies in the war on terror and friends and he's much concerned as I am, as the Afghan people are."
He also told the BBC that the Taleban would continue its kidnapping policy whether or not there was an exchange.
Mr Bush said the Taleban were to blame for civilian casualties, while Mr Karzai labelled the Islamist militants "merchants of death," who were prepared to use child suicide bombers.
In Seoul, a South Korean presidential spokesman said the government wanted to "work separately" from the Bush-Karzai summit to resolve the issue.
The Afghan leader said: "The message should be clear to the rest of the world about the evil we are fighting, the heartless people we are fighting who don't even have any feeling for young children or babies."
"It is inappropriate to have any premature expectations or to overly interpret the summit," he said.
Praising his Afghan counterpart, Mr Bush said: "There is still work to be done, don't get me wrong. But progress is being made, Mr president, and we're proud of you."
About 100 protesters rallied near the US embassy in Seoul on Monday and handed in a letter addressed to Mr Bush.
Mr Bush said they had stymied Taleban plans for a major spring offensive with a show of force.
A demonstrator in Seoul protests against US policy in Afghanistan
He said: "There's a spring offensive alright - it was conducted by the US, Nato and, equally importantly, Afghan troops.
"The US must assume responsibility for the kidnapping of our people in Afghanistan. The incident was caused by the US war of aggression," it read.
"We went on the offensive as we understand it's in our mutual interest to deny extremists the opportunity to derail this young democracy."
Two of the hostages are said to be seriously ill and a private Afghan clinic said antibiotics, pain killers, vitamins and heart pills had been left in an area of desert in Ghazni province, where the hostages are being held, as specified by the militants.
Mr Bush also took the opportunity fire a shot across the bows of Iran, labelling that country a "big disappointment" for its people.
An official in Seoul said the South Korean government had had its first telephone contact with one of the hostages on Saturday.
"I believe it is in the interests of all of us that we have an Iran that tries to stabilise not destabilise, an Iran that gives up its weapons ambitions and therefore we are working to that end," he said.
The Yonhap news agency said it had also spoken to hostages by telephone and was told they had been split into several groups.
It reported one captive as saying: "We are all sick and want to meet our families again at home... the Taleban point guns at us and threaten to kill us if the Korean government does not accept their demands."
Plans for a direct meeting between negotiators and the Taleban have yet to overcome problems about a venue.
In Washington, Mr Karzai said he would do everything he could to have the hostages released, short of "anything that will encourage hostage-taking, that will encourage terrorism".
Iran disagreement
Other key items on the Karzai-Bush agenda are likely to be the growing number of civilians killed in coalition military operations, the drug trade and economic development.
Mr Karzai is concerned about the number of civilian casualties
Mr Bush is also expected to urge Mr Karzai to root out corruption.
One apparent matter of dispute was Iran.
The US has accused Tehran of supplying weapons to the Taleban.
But Mr Karzai appeared to deny such claims in an interview with CNN.
"Iran has been a supporter of Afghanistan, in the peace process that we have and the fight against terror, and the fight against narcotics in Afghanistan," he said.
Mr Karzai also said there was no encouraging news on the whereabouts of al-Qaeda leader Osama Bin Laden.
"We are not closer, we are not further away from [finding him]. We are where we were a few years ago," Mr Karzai said.
The Afghan president is also concerned about increasing civilian deaths in coalition military operations. Recently he accused the coalition of "extreme use of force".
