KABUL, April 28 (Xinhua) -- The Taliban on Friday announced the start of their yearly rebel offensive in Afghanistan.
The Taliban has codenamed their offensive "operation Mansoori" referring to their leader Mohammad Akhtar Mansoor who was killed in a U.S. drone strike along the Afghanistan-Pakistan border last year, they said in a statement.
The Taliban militants, who ruled the country before being ousted in late 2001, renewed armed insurgency, killing government troops as well as civilians.
They urged civilians to stay away from official gatherings, military convoys and centers regarded as the legitimate targets by militants besides warning people not to support the government.
The NATO and U.S. forces completed their combat mission in Afghanistan by the end of 2014, after 13 years of military presence in the country but around 13,000 foreign troops remain in the country to train and assist the Afghan forces.
On Thursday, the UN urged warring sides in Afghanistan to take further measures for better protect of civilians from conflicts.
"With the so-called fighting season imminent, I appeal to all parties to take every measure possible to prevent unnecessary and unacceptable harm to Afghan civilians," Tadamichi Yamamoto, special UN envoy and head of the UN Assistance Mission in Afghanistan, said in a statement.
"During an armed conflict, the intentional killing and injuring of civilians is a war crime," said Yamamoto, adding that "anti-government elements must stop this deplorable practice and everybody must apply - and respect - the definition of 'civilian' provided by international humanitarian law."
About 715 civilians were killed and over 1,460 others injured in conflict-related incidents across Afghanistan in the first three months of the year, according to figures released by the UN mission in the country.
The mission attributed 62 percent of the casualties to the Taliban and other anti-government militants.