Germany wants to keep the door ajar for invited Afghans to flee to Europe – but not push it open so wide that a flood of refugees ensues.
Foreign Secretary Heiko Maas said there could be no repeat of the chaos in Kabul, where people with no visas or passports crowded outside the airport in the hope of escaping the Taliban.
Europe is determined to avoid a rerun of the 2015 refugee crisis when more than a million people crossed EU borders to seek asylum.
But Nato countries want their own citizens and Afghans who helped western troops to have a way out, after some people were left behind by the two-week airlift.
Visiting Uzbekistan on Monday, Mr Maas said Berlin had stressed to the government in Tashkent that it only wanted to extract a limited number of people.
He said potential land routes out of Afghanistan should not become public knowledge and would have to be negotiated with the Taliban.
“There is one thing we want to prevent, which is a repeat of what happened in Kabul – that contact and gathering points are publicly named, and those we want to extract get there but 10,000 others are already there,” he said.
Mr Maas said Uzbekistan had agreed to help with people on Germany’s rescue list, after Nato pilots used the capital Tashkent as a stopping point on the way to Europe.
“We did not make any requests beyond that,” he said. “It is only about this group of people.”
Britain has described safe passage out of Afghanistan as a key demand for any international engagement with the Taliban.
Ministers in the UK estimate that between 800 and 1,100 Afghans were left behind. The opposition says the numbers could be much higher.
Western countries hope that the Taliban can be persuaded to allow commercial flights out of Kabul airport once the Nato withdrawal is complete.
But resuming flights could take time because of damage to the airport, Mr Maas said. A terrorist attack at the gates last week killed dozens of people.
In the meantime, some Afghans have headed for the borders. Iran and Pakistan already host hundreds of thousands of refugees.
Europe considers Afghanistan’s neighbours, including Uzbekistan, Tajikistan and Pakistan, as key partners in preventing a fresh refugee wave.
The UN refugee agency, UNHCR, said on Monday that more than half a million people had been displaced since the start of the year.
UNHCR chief Filippo Grandi said the aid response was desperately short of funding and Afghanistan’s neighbours needed greater support.
“The airlifts out of Kabul will end in a matter of days, and the tragedy that has unfolded will no longer be as visible,” he said.
“But it will still be a daily reality for millions of Afghans. We must not turn away. A far greater humanitarian crisis is just beginning.”
Germany plans to provide €500 million ($590m) in humanitarian aid to Afghanistan and its neighbours to help people who cannot leave.
After moving on to Tajikistan later on Monday, Mr Maas said Germany wanted to provide “very practical help to affected people” in the region.
“We as a government want to send a clear signal that we are not just aware of the situation and holding talks about it, but taking action,” he said.
While Mr Maas travels to Pakistan on Tuesday, EU home affairs ministers will discuss the issue at an emergency summit in Brussels.
The ministers will express their determination to prevent another refugee crisis by mounting a “co-ordinated and orderly response”, according to a draft seen by Reuters.