Foreign Minister Salahuddin Rabbani on Wednesday welcomed a renewed commitment by NATO members for financial aid to Afghan security forces until 2020.

"Taking this opportunity, I reiterate the appreciation of the people and Government of Afghanistan for NATO's renewed commitment to continue national contributions for the financial sustainment of our Afghan National Defense and Security Forces, until the end of 2020," Rabbani said adding that "we also commend the important work of the Resolute Support Mission for training, advice and assistance to our national security institutions."

"The Warsaw Summit has generated renewed confidence in our national army and police as they defend Afghanistan's territorial integrity and national sovereignty against the evil forces of terrorism and violent extremism," he said.

Earlier in the day, NATO Secretary-General Jens Stoltenberg warned that the situation in Afghanistan remained "difficult and tough" and said the alliance will continue to train and support Afghan security forces fighting "terrorism" on the ground.

Afghanistan has been facing major political and security challenges since the withdrawal of international combat troops at the end of 2014.

Stoltenberg also said that the National Unity Government (NUG) received financial and political support from the international community and in exchange must fulfill its commitments.

He also spoke about insurgency and said the security situation in Afghanistan is complicated.

"These are clear signals of the continued commitment of the international community. The security situation in Afghanistan remains difficult but the Afghan Security Forces are responding with great bravery and professionalism.

"NATO Allies and partners continue to support them politically, practically and financially. In return, Afghanistan made commitments to step up reforms and improve governance. We will review all these mutual commitments today," he said.

Although NATO announced its continued support to Afghanistan, President Barack Obama has said the U.S cannot defeat Taliban in Afghanistan and that violence will continue to exist in the country.

There are about 13,000 foreign troops currently stationed in Afghanistan of whom more than 9,000 are Americans.