Baghdad, Iraq ? Three militant groups warned Iraqis against voting in Jan. 30 elections, saying Thursday that people participating in the “dirty farce” risked attack. All 700 employees of the electoral commission in Mosul reportedly resigned after being threatened.

The warning came a day after insurgents in Mosul, which has seen increased violence in recent weeks, launched a highly coordinated assault on a U.S. military outpost. The United States said 25 insurgents were believed slain and one American soldier was killed in the battle, which involved strafing runs by U.S. warplanes.

The United States, which has said the vote must go forward, has repeatedly sought to portray recent attacks that have killed dozens of people as the acts of a reeling insurgency, not the work of a force that is gathering strength.

The radical Ansar al-Sunnah Army and two other insurgent groups issued a statement Thursday warning that democracy was un-Islamic. Democracy could lead to passing un-Islamic laws, such as permitting homosexual marriage, if the majority or people agreed to it, the statement said.

“Democracy is a Greek word meaning the rule of the people, which means that the people do what they see fit,” the statement said. “This concept is considered apostasy and defies the belief in one God — Muslims’ doctrine.”

Ansar al-Sunnah earlier posted a manifesto on its Web site saying democracy amounts to idolizing human beings. Thursday’s joint statement reiterated the threat that “anyone who accepts to take part in this dirty farce will not be safe.”

Insurgents have intensified their strikes against the security forces of Iraq’s U.S.-installed interim government as part of a continuing campaign to disrupt the elections for a constitutional assembly. Iraqis will elect a national assembly that is to write a new constitution.