The White House says President George Bush and Iraqi Prime Minister Nouri al-Maliki have agreed to set a "time horizon" for reducing U.S. forces in Iraq.

A White House spokeswoman says the two leaders spoke Thursday by secure video conference. She says they agreed that a withdrawal of U.S. troops from Iraq would be based on continued improvement in security conditions and not an arbitrary date.

Iraqi officials have been pressing Washington to accept a timeline for withdrawing U.S.-led forces.

President Bush has been opposed to naming a specific date for withdrawing troops, saying the withdrawals should be determined by Iraq's security conditions.

In other news, the U.S. Defense Department says it has no indication that Iran has reduced what it calls "meddling" in Iraq, even though the number of attacks by Iranian-backed militias are down significantly.

A Pentagon spokesman says the recent 70 percent drop in roadside bomb attacks resulted from efforts by Iraqi and U.S. security forces to eliminate insurgent safe havens.

The U.S. has accused Iran of supporting militants in Iraq, a charge Tehran denies.

The U.S military in Iraq Friday said coalition forces captured five so-called special group criminals, including a suspected financier of Iranian-sponsored insurgents.

A statement said coalition forces staged the raid in the Admhaiyah section of Baghdad, about three kilometers northwest of Sadr City.

The U.S. military uses the special groups designation to describe Shi'ite insurgents backed by Iran.

Some information for this report provided by AP, AFP and Reuters.