KABUL (Reuters) - The Nato-led coalition in Afghanistan is expecting Taliban-led insurgents to launch a series of major attacks across the country over the next week, senior military officials said on Friday. They said recent intelligence reporting indicated that the attacks planned by the Taliban, supported by the al Qaeda-linked Haqqani network and other insurgents, would include suicide bombings. Two senior coalition commanders said they anticipated the campaign of increased violence would last about a week. "The enemy can generate indiscriminate violence but he can't succeed," one of the coalition commanders told Reuters. "We're expecting a big spike in violence over the next week." Washington and commanders of the Nato-led ISAF have trumpeted successes against a growing insurgency since 30,000 extra US troops were sent to Afghanistan last year. Military commanders interviewed by Reuters were not sure why May 1 had been chosen by the Taliban to launch their renewed offensive. The anticipated Taliban campaign would not change the coalition's counterinsurgency strategy put in place last year by US General David Petraeus, the commander of the 150,000 US and ISAF troops in Afghanistan, they said. Under a programme agreed at a NATO summit last year, ISAF will begin handing security responsibility to Afghan forces in several areas from July. The programme will end with the withdrawal of all foreign combat troops by the end of 2014. A senior US defence official in Washington said fighting was expected to rise and could peak in the next 12 months. But that would not prevent the United States from going ahead with the scheduled troop drawdown from July. He said the Taliban were still able to mount major attacks but posed less of a strategic threat than in the past. "Again, that doesn't mean that day-to-day there aren't big challenges," the US defence official said. NATO-led military commanders briefed Afghan government officials and Western diplomats about the expected spike in violence over the past few days. "These incidents can't derail the transition process but, at the same time, it shows the fragility of the situation," one senior Kabul-based Western diplomat told Reuters. Another NATO military commander said they expected the Taliban to try and regain ground lost to ISAF and Afghan forces since the extra US troops were sent in. "We're tracking credible intelligence that senior Taliban leaders, backed by the Haqqani network, plan to conduct attacks throughout Afghanistan from the end of April," he said. "They're attempting to regain momentum after the progress by the coalition over the last year." Both senior coalition commanders in Kabul said the Taliban offensive would likely include ambushes, suicide bombings and attacks against high-profile targets in the capital, Kabul, and other major cities including Kandahar and Lashkar Gah in the south, in the north and in Herat in the west. The attacks, they said, would most likely be concentrated in the east, near Afghanistan's long and often-porous border with Pakistan, where Taliban fighters have long sheltered in safe havens and from where they often launch attacks.