KABUL, Afghanistan —  Landmark legislative elections in Afghanistan (search) will be held as planned in September despite an upsurge in rebel violence that has raised fears the polls could be threatened, the president's spokesman said Tuesday.

President Hamid Karzai's (search) spokesman said that the elections "will be successful."

"I would like to emphasize that Afghanistan will not go back ... the progress we have made can never be reversed regardless of how hard the terrorists and the enemies of Afghanistan try," spokesman Jawed Ludin told reporters.

His comments come after three months of unprecedented fighting that has killed a reported 465 suspected terrorists, 29 U.S. troops, 38 Afghan police and soldiers and 125 civilians.

The violence has left much of the country off-limits to aid workers and has reinforced concerns that the war here is not winding down but in fact worsening into an Iraq-style conflict.

Last week, the United Nations' (search) top envoy for Afghanistan, Jean Arnault, warned in New York that the bloodshed threatens the Sept. 18 elections — the next key step toward democracy after a quarter century of war.

He said the insurgents have more money, better weapons and good radios to spread propaganda ahead of the parliamentary vote. The envoy warned that the rebels "are demonstrating increased cruelty and blind violence."