TASHKENT/BEIJING -- China and Russia have proposed economic assistance to fragile neighbor Afghanistan as a relentless Taliban offensive and looming U.S. exit threaten to spill turmoil across their borders.

"China will support the development of roads and pipelines in Afghanistan," Chinese Foreign Minister Wang Yi said at the inaugural conference for Central and South Asia ties in the Uzbek capital Tashkent this week.

The two-day event through Friday, which also drew Russian Foreign Minister Sergey Lavrov and other senior officials from across the region, focused on how to promote peace and economic recovery in Afghanistan. Investment was a main topic of the discussions.

Afghan President Ashraf Ghani, who was in Washington last month to try to persuade the U.S. to keep supporting Afghan security forces against the Taliban insurgency, said he welcomed investments in his country.

Afghanistan hopes to become a regional hub to drive mutual economic advancements, Ghani said.

With U.S. forces set to exit Afghanistan completely by the end of next month, China and Russia fear growing unrest.

"The Afghan crisis is aggravating the threat of terrorism and illegal drug trafficking, which has grown to an unprecedentedly high level," Lavrov said. "It is obvious that the current situation is fraught with the danger of a spillover of the instability into neighboring states."

The conference in Uzbekistan followed a gathering on Wednesday of foreign ministers from the Shanghai Cooperation Organization, which includes China, Russia and Central Asian nations, in the Tajik capital of Dushanbe.

"We condemn the ongoing violence and terrorist attacks in Afghanistan," the ministers, including Afghanistan's Mohammad Haneef Atmar, said in a joint statement, adding that "there is no alternative to settling the conflict in Afghanistan through political dialogue and an inclusive Afghan-led and Afghan-owned peace process."

China and Russia maintain connections with the Taliban, which has taken control over half of Afghanistan in an ongoing offensive against government forces. Beijing and Moscow would likely not oppose an attempt by the group to regain its grip on the Afghan government, either in cooperation with the current administration or some other force in the region.

A Taliban delegation visited Moscow on July 8 to assure Russian officials that their gains were not a threat. Meanwhile, Wang welcomed the Taliban back to the political mainstream in June.

Countries are especially concerned about a potential influx of refugees and extremist cells. Over 1,000 Afghan soldiers fled to Tajikistan and elsewhere on July 4-5 amid clashes with the Taliban. A Wednesday blast on a bus in Pakistan killed at least 13, including several Chinese workers.

In addition to the Taliban, the Islamic State and al-Qaida also operate in Afghanistan, further muddling the country's future following the U.S. withdrawal. China in particular worries that the East Turkestan Islamic Movement, which Beijing has designated a terrorist organization, could join hands with the Taliban in Afghanistan and infiltrate the restive Xinjiang region. Xinjiang is home to much of China's Uyghur Muslim minority.

Over 20 years have passed and 2,000 American troops have died since the U.S. launched a war in Afghanistan in 2001, following the 9/11 terrorist attacks.

"Countries in the region have an essential role to play in supporting a peaceful settlement," U.S. President Joe Biden has said, urging regional cooperation during and following the U.S. withdrawal.

But China and Russia have slammed the U.S. for withdrawing combat forces from the country. Leonid Slutsky, chairman of the State Duma Committee on International Affairs in Russia's legislature, said the U.S. plans "seriously complicated the already complex situation."

Wang said the U.S. is trying to shirk its responsibilities.