Washington (CNN) -- The Taliban said Saturday it is launching a new offensive against foreign troops and Afghan security forces in what it calls the tenth year of "sacred Jihad against all foreign invaders."
Declaring its spring military operations, the Taliban said it will focus on attacks against military bases, airbases, convoys, heads of foreign and local companies, and members of the local government.
It also views as enemies members of the High Peace Council, influential citizens who have been trying to generate dialogue with the militants.
"All Afghan people should bear in mind to keep away from gatherings, convoys and centers of the enemy so that they will not become harmed during attacks of the Mujahideen against the enemy," the statement said.
The Taliban said "strict attention" must be paid to protecting civilians.
"Utilizing all proven military tactics, the operations will focus on usage of advanced weapons against the air and ground forces of the invaders, tip-and-run attacks, and group offensives, city attacks, advanced explosives attacks, effective group and martyrdom seeking attacks by warrior Mujahideen," the statement said.
The Taliban regime in Afghanistan had been sheltering the al Qaeda terror network when it launched attacks against the United States on September 11, 2001. The United States cranked up military operations the next month that led to the toppling of that government.
Ever since, international forces have been fighting Islamic militants in Afghanistan and Pakistan and attempting to support and build the successor Afghan government.
The Taliban announcement comes a day after a NATO official told CNN that the alliance anticipates insurgents to begin an extensive new round of attacks against U.S. and coalition forces "in the coming days."
The officer with NATO's International Security Assistance Force noted that the alliance has seen similar surges at this time in recent years.
"What basically they are trying to do is start their spring offensive and they think by surging their forces and having a concentrated series of attacks that they can demonstrate their power and relevance, and influence over the Afghan population."
ISAF feels the increased coalition attacks on insurgents have had an impact, and new attacks by insurgents signal their effort to recoup their losses.
"Over the past several months insurgents have suffered a number of setbacks, having been pushed out of key sanctuaries. They have lost more weapons caches than any previous year and they have lost hundreds of insurgent commanders and thousands of fighters," the officer said.
In a statement on Saturday addressing the expected escalation in fighting, the United Nations Assistance Mission in Afghanistan urged all parties to avoid harming civilians.
Staffan de Mistura, head of the mission, called on the Taliban "to carry out their previously stated decision to avoid civilian casualties."
"Parties to the conflict must not deliberately attack, target or kill civilians, or indiscriminately harm them," said de Mistura, who was quoted in the statement. "We call on all parties to take all possible measures to protect civilians, especially in the forthcoming months when we expect, unfortunately, intensified conflict."
He noted the Taliban vow to target government officials, lawmakers, foreign and Afghan business leaders, and members of the High Peace Council.
"The United Nations calls on the Taliban to refrain in particular from attacking all such persons who are not taking a direct part in hostilities," the mission said.
The U.N. office also cautioned the Taliban over the "indiscriminate use" of roadside bombs.
"Warring parties are obliged not to launch attacks on civilian locations or in areas where civilians gather such as government buildings, bazaars and parks," the statement said.
Likewise, it said pro-government forces must avoid civilian casualties in its airstrikes and night raids. Troops must "strictly enforce international laws and tactical directives that regulate air strikes" and night raids "must fully respect Afghan cultural and religious practices and minimize harm to civilians."
In the 90 days ending April 22, coalition special forces conducted 1,393 operations, capturing or killing 468 insurgent commanders, and capturing or killing 2,637 lower-level insurgents.
In response to the latest intelligence, ISAF has "increased" measures to protect its forces as well as sharing the intelligence with the Afghan government, the ISAF officer said.
The expectation is new attacks would continue to focus on the latest Taliban tactics of assassinations, small arms attacks and going after so-called "soft" targets of Afghan civilians. The officer also said the alliance is watching for more of the "impersonation and infiltration-type attacks that you have seen in the last several days."
He noted that the alliance remains uncertain if recent attacks by Afghans in military uniforms really are the work of impersonators loyal to the Taliban. ISAF is currently helping train 450 counterintelligence experts in the Afghan forces to help watch for such activity, a doubling of the current counterintelligence force.
This all comes as the Pentagon released its latest report to Congress on the progress in Afghanistan. The military says gains made in Afghanistan over the last half year has created the "necessary conditions" to begin transferring control of security to the Afghanistan government in seven areas of the country inhabited by approximately 20% to 25% of the population.
The latest semi-annual report concludes insurgent momentum has been halted in much of the country, though the gains are "fragile and reversible." However, the report notes that efforts to fortify government and development was "slower than security gains" over the last six months.
The total number of security incidents were higher from October 2010 through March 2011 compared to the same period of the winter of 2009-2010 the report said. The report says this is mainly due to increased ISAF and Afghan troop presence, which allowed for a higher pace of operations against insurgents safe havens.
CNN's Adam Levine and Joe Sterling contributed to this report.