The Independent Monitoring Commission has blamed the UVF for five murders and 15 attempted murders as part of its feud with the LVF.
IMC report lists the murders it said had been part of the feud
A special report said the LVF carried out two murder bids, but their violence was mainly a response to UVF attacks.
Its report on the loyalist feud led NI Secretary Peter Hain to declare the UVF ceasefire had broken down.
Almost 150 people have been warned by the police that their lives may be in danger as part of the feud, it said.
The commission said it believed the UVF leadership had decided that "now was the time to finish off their rivals".
The IMC noted statements by the Progressive Unionist Party (PUP) indicating that they could not stop the feud, but said the PUP could not have it both ways.
They must disassociate themselves from the UVF or accept the consequences, it said.
The PUP is linked to the UVF and Red Hand Commando.
The IMC report lists the murders it said had been part of the feud.
The five murders were: Michael Green (42) shot dead in Sandy Row on 15 August; Craig McCausland (20) shot dead in his Dhu Varren Park home in north Belfast on 11 July; Stephen Paul (28) shot dead in Wheatfield Crescent in north Belfast on 30 July; Jameson Lockhart (25) shot dead on the lower Newtownards Road on 1 July; Brian Stewart (34) shot dead in east Belfast on 18 May last year.
However, the IMC also said it had no reason to believe that either the murder of Bangor woman Lisa Dorrian in February 2005 or the murder of teenager Thomas Devlin last month were carried out on behalf of a paramilitary organisation.
"We are aware of the view that the PUP is not strong enough to influence the UVF - in effect that it is the UVF rather than the PUP which now leads.
"No democratic political party can expect to have it both ways. It can either disassociate itself from the paramilitary group, or it must accept the consequences of its association."
It added: "We believe there is still an association between the PUP and UVF.
"We think now, as we have before, that the PUP has not done all that could be done to prevent paramilitary activity and has not credibly voiced or exerted its opposition to paramilitaries, and the UVF in particular."
The IMC said the police had already been stretched by fighting organised crime in Northern Ireland and have had to divert resources to the feud.
"They have made 45 arrests since the beginning of July 2005.
"Fifteen people have been charged and 126 searches undertaken. Since July 1, they have informed 146 people that they may be under threat as a result of the feud."
Irish Justice Minister Michael McDowell said: "I strongly condemn the recent feuding between rival loyalist paramilitary groups, which has resulted in four murders since July of this year alone.
"I fully support the IMC's decision to highlight the pain and damage inflicted upon the communities these groups purport to represent."
Alliance Party leader David Ford said the report made "chilling reading".
"In their report, the IMC are quite clear that it is time that the government should focus on the wide range paramilitary and criminal activity rather than narrow definitions of a ceasefire.
"All such activity is a threat to the rule of law and to democracy."
IMC said police had been stretched by fighting organised crime
In July, Northern Ireland Secretary Peter Hain said he intended to withhold the PUP's assembly allowances for another year.
The decision followed the previous report from the Independent Monitoring Commission, which said the UVF and Red Hand Commando remained active, violent and involved in organised crime.
The Independent Monitoring Commission was set up by the British and Irish governments in January 2004.
It is a crucial element in the two governments' plans for restoring devolution, which was suspended in October 2002 amid allegations of IRA intelligence gathering at the Northern Ireland Office.