BAGHDAD, March 19 (UPI) -- Iraqi security officials operating with U.S.-led forces uncovered several weapons caches and arrested at least four others in raids throughout the country.

The U.S. military reported in various statements that security forces uncovered anywhere from eight to 17 weapons caches throughout various parts of Salah ad Din province.

Statements from Multi-National Corp-Iraq said the caches contained everything from ammonium nitrate, a fertilizer that can be used as an explosive, to several dozen mortar rounds and a variety of other explosives.

The latest weapons caches bring the total number of ordnance uncovered in northern Iraq to 591 since January.

Meanwhile, Iraqi police units Wednesday arrested four suspects "wanted for involvement in different crimes" and defused a roadside bomb in Missan province near the southeastern border with Iran, Voices of Iraq said.

A source for VOI said an Iraqi police squad defused the bomb uncovered north of the provincial capital, Amarah.

In a village southwest of Kirkuk, Iraq police arrested a man in the process of rigging a car with explosives. VOI said police also confiscated a number of weapons from the man's home.