[14] Only lightly armed police in groups of up to ten were allowed to patrol,[16] and banned the FRY from using planes, tanks or any other heavier weapons.

[19][20] The group began attacking Serbian civilians and police, with the goal of joining Preševo, Medveđa and Bujanovac into Kosovo, which escalated into an insurgency.

[21] Due to the FRY's inability to use any heavy weapons against the UÇPMB, the group expanded and occupied all villages related to Sectors B and C east, with the exception of Gramada.

After the overthrow of Slobodan Milošević on 5 October 2000, Vojislav Koštunica wanted the United States to reduce or disband the GSZ,[22] with KFOR mediating a ceasefire on 24 November.

[29][30] These fierce battles, witnessed by NATO, were the starting point for the VJ to enter the GSZ, called Operation Return.

On 14 March 2001, at 6:30 am, after the fiercest fighting in the area since the Kosovo War,[31] NATO allowed Yugoslav forces into Sector C east.

[13] The president at the time, Vojislav Koštunica, was told by Nebojša Pavković that the operation was going successfully, as the troops found no mines nor any UÇPMB rebels.

On 12 April 2001, an agreement was signed between Krstić and Nebojša Čović, the head of Coordination Center for Southern Serbia,[33] along with KFOR representatives.

[34] On 21 May 2001, Shefket Musliu, Mustafa Shaqiri, Ridvan Qazimi, and Muhamet Xhemajli signed the Končulj Agreement,[35][36] which resulted in the full demilitarization, demobilization, and disarmament of the UÇPMB.

The first Yugoslav troops entered Sector B on 24 May 2001, with occupying 90 percent of the B south and B center zones without any confrontations from UÇPMB rebels.

An hour and thirty minute battle with the UÇPMB in Veliki Trnovac had left commander Ridvan Qazimi dead, where it had been revealed he had been killed by a sniper.