KABUL (AFP) - The top UN official in Afghanistan on Tuesday urged the Taliban not to disrupt elections, as fighters killed nine people, ambushed a presidential campaign manager and fired rockets into a UN compound. A surge in attacks by Taliban and other militants battling the government and allied Western troops has raised concerns that insecurity will lead to poor voter turnout and throw into doubt the legitimacy of the August 20 poll. In eastern Laghman province, a campaign manager for leading presidential candidate Abdullah Abdullah was shot as he travelled to a gathering and his nephew, who was driving, was killed. His vehicle was attacked on the way to the district. His driver was killed and he is wounded, Murtaza Qalandarzai, deputy provincial governor, told AFP. Abdullah was not present at the time. It was the second attack in as many days on Abdullahs campaign and came after a running mate of President Hamid Karzai escaped unharmed when militants armed with guns and rockets ambushed his convoy on Sunday. In the south, a remote-controlled bomb planted by insurgents ripped through two vehicles and killed eight Afghan private security guards in the province of Helmand on Tuesday, the government said. One civilian was wounded in western Herat province when one of a salvo of rockets directed at a UN compound smashed into a nearby house, regional police chief Ikramuddin Yawar told AFP. Seven rockets were fired, of which two landed inside the compound, but no staff were hurt and offices remained open, a UN statement said. Afghanistans intelligence service said its spies arrested three men, who confessed under interrogation to planning suicide attacks in central Kapisa province in a bid to disrupt the electoral process. Kai Eide, head of the UN Assistance Mission in Afghanistan (UNAMA), acknowledged significant security concerns. There have been some attacks on candidates... This is a matter of great concern, Eide told reporters in Kabul. My message to everybody including Taliban is it is in the interests of each and every Afghan that elections can take place in each province, in each district, in each village, so that all Afghans can express their views and cast their vote, he said.