"There is a declining role for a significantly degraded al-Qaida and a rising role for groups inspired by al-Qaida," State Department counsel Philip Zelikow said at a briefing on the department's first Country Reports on Terrorism.
But al-Qaida itself remained "the primary terrorist threat to the United States in 2004", the document said.
The report cited as examples the March 2004 bombing of commuter trains in Madrid, Spain, and an Algerian terrorist leader's announcement of loyalty to Usama bin Ladin's al-Qaida.
The incidents "illustrate what many analysts believe is a new phase of the global war on terrorism, one in which local groups inspired by al-Qaida organise and carry out attacks with little or no support or direction from al-Qaida itself", the report said.
The report expanded on testimony to the Senate Intelligence Committee in February from CIA Director Porter Goss.
Al-Qaida still dangerous
He spoke of gains against al-Qaida and its affiliates but warned that they remained dangerous.
Attacks such as the Madrid bombs
are seen as a growing threat
Jointly with the State Department report, the new National Counter-terrorism Centre issued a compilation of international terrorism incidents last year.
It said 651 significant international terrorist attacks caused 9321 casualties worldwide, including 1907 deaths.
The dead, wounded or abducted included 103 Americans, or 1% of the total.
On Tuesday, Representative Henry Waxman, a Democrat from California, said the 651 attacks were triple the 2003 number but told Secretary of State Condoleezza Rice the report probably understates the toll.
Zelikow said the toll is irrelevant to last year's, because the terrorism centre had greater manpower and resources to put into the project than the State Department had.
The country reports credited Pakistan for its work in curtailing the effectiveness of al-Qaida, blamed for the 11 September 2001 attacks on the United States and other strikes around the world.
"I do believe we are winning the war on terrorism, but I believe it will be a very long struggle"
US State Department counsel
"Al-Qaida leadership was degraded through arrests and ongoing Pakistani operations to assert greater control along the border with Afghanistan where some al-Qaida leaders are believed to hide," the report said. "Numerous al-Qaida and affiliated foot soldiers were captured or killed during the year."
Still, it said, "many senior al-Qaida leaders remained at large, continued to plan attacks against the United States, US interests and US partners".
Additionally, the fugitives "sought to foment attacks by inspiring new groups of Sunni Muslim extremists to undertake violent acts in the name of jihad", it said.
Winning the war
Some of the events were carried out by groups whose existence became known only after the attacks, the report said.
"I do believe we are winning the war on terrorism, but I believe it will be a very long struggle," Zelikow said.
Until now, the State Department has been the government's principal authority on terrorism.
It has distributed figures with its annual Patterns of Global Terrorism, based on definitions of terrorism established by Congress in legislation that ordered distribution of the annual terrorism report.
Last year's report caused problems for the State Department after it was learned that it greatly understated the number of incidents that had occurred.
On Wednesday, House Democratic leaders asked the department's acting inspector-general Cameron Hume to investigate whether the mistakes were politically motivated.
The National Counter-terrorism Centre is working on a new list, to be released in June that will use new, more realistic, definitions of terrorism.
"Al-Qaida leadership was degraded through arrests and ongoing Pakistani operations to assert greater control"
US State Department report
"It is going to be a much more comprehensive data set," said John Brennan, the centre's interim director, and will be likely to encompass many additional incidents.
As an example of the rules for the listings distributed on Wednesday, under which the State Department and his centre have operated, Brennan said the report lists only one of two Russian planes that bombers destroyed last year.
The one that counted had an Israeli on board. The other had all Russians, which made it a domestic incident.
"It makes no sense to have the definition of terrorism depend on checking the nationality of all the victims," Brennan said.