Two days of international talks on Afghanistan got under way in Brussels on Tuesday, overshadowed by clashes in the northern Afghan city of Kunduz between security forces and Taliban militants.

The conference will bring together more than 70 countries and up to 30 international organizations to pledge political and financial support towards the development of the war-torn country until the end of 2020.

With billions of dollars of aid packages spent in Afghanistan over the last 15 years, it is still one of the poorest and politically unstable countries in the world, while corruption is rife.

Security remains a major concern, as poorly trained and equipped Afghan troops struggle to keep the Taliban at bay, while the DAISH militants become a growing threat.

The aim of the Brussels talks, hosted by the European Union, is to keep funding for the next four years on a par with the 4 billion dollars annually pledged in 2012.

Ahead of the meeting, the Amnesty International campaign group warned donors against making any pledges conditional on Kabul's acceptance of returned migrants, after papers were leaked according to which the EU was mulling the return of 80,000 Afghans.

On Sunday, the bloc struck a deal with Kabul, which aims to expedite travel documents and allow the use of Afghan airports, while the EU would pay for flights and reintegration program, according to DPA news agency.

Afghan Special Forces have managed to wrestle back control of the vulnerable northern city of Kunduz from Taliban fighters, who had managed to overrun the city almost exactly a year after pulling off a similar takeover of the city. Afghan forces announced late Monday they had reclaimed the city after the Taliban earlier managed to break through and raise their flag in the center of capital of the Tajikistan-bordering Kunduz province. According to the government, 25 Taliban fighters have been killed in the response and many more wounded.

Afghan forces also managed to reclaim Nawa district in restive Helmand province shortly after also losing it to the Taliban. In a series of tweets, the NATO-led Resolute Support Mission in Afghanistan also said the Afghan forces are back in control but they will continue to provide support where needed.

In June, U.S. President Barack Obama granted new powers for his U.S. forces to assist Afghan troops against the Taliban, even though the rest of NATO plays a more limited role after ending its combat mission in Afghanistan at the end of 2014.