There have been serious disagreements between Taliban leaders and their fighters within the Taliban's leading council, National Directorate of Security (NDS) said on Wednesday.

The differences among the Taliban leaders and their fighters have made the Taliban to step up suicide attacks in cooperation with al-Qaeda network in a bid to conceal their defeat in Afghanistan, NDS Spokesperson Lotfullah Mashal said.

Mr Mashal said a number of foreign insurgents with crucial role in recent wave of attacks in northern Afghanistan have been detained.

He said military pressures by Afghan and foreign troops have forced out insurgents to hide somewhere in Pakistan and refuse to resume their fight in Afghanistan.

"There have been differences of opinion between low and high level Taliban leaders within Taliban's Quetta Shura, Haqqani network and Taliban's council in Peshawar," Mr Mashal said.

An increase in suicide attacks in the north and especially in Kunduz province is a sign of Taliban's failure and panic, he said.

The Taliban have lost all their strongholds and their momentum has been reversed in most all parts of the country, he said.

National security department said two Ukrainian militants along with their Afghan associates have been arrested.

Until insurgent sanctuaries beyond the Afghan borders are not rooted out, the counterinsurgency fight would not lead to victory, he said.