Afghanistan has seen an "alarming" 94 per cent increase in incidents involving homemade bombs in a year, a report by the United Nations secretary general said on Saturday.
Ban Ki-moon said "security incidents" have risen significantly in Afghanistan as US-led forces make a push in the south and militant activities have grown in southeast and eastern regions.
"The rise in incidents involving improvised explosive devices constitutes an alarming trend, with the first four months of 2010 recording a 94 per cent increase compared to the same period in 2009," the report to the UN security council said.
Improvised bombs have made up one third of reported incidents of violence in Afghanistan this year while suicide attacks are happening at a rate of about three a week, it said. It added that suicide attacks involving more complex planning have doubled from last year to roughly two per month.
"The shift to more complex suicide attacks demonstrates a growing capability of the local terrorist networks linked to Al Qaeda," the report said.
Assassinations of civilians by insurgents aiming to take control of urban populations have also increased 45 per cent from last year, to a rate of seven a week, mostly taking place in Afghanistan's south and southeast, it added.
NATO troops and Afghan security forces have for weeks been engaged in a surge of counter-insurgency operations around the southern city of Kandahar, aimed at re-establishing central government authority there.
The Pentagon said this week US-led forces were making headway against the Taliban, but it was "overshadowed" by violence in southern provinces and what it called an overly gloomy portrayal of the war shaped by media coverage.
US President Barack Obama has ordered a surge that will see troop numbers, currently estimated at 142,000, to peak at 150,000 by August, before an intended drawdown in 2011.