Iraqi President Jalal Talabani was angered by the arrest of an Iranian national who was part of a trade delegation and asked the US forces to immediately release him, media reports said Sunday.

The leader sent “a letter of anger” to US ambassador to Iraq Ryan Crocker and General David Petraeus, the top commander of US forces in the strife-torn country. Talabani demanded the release of the Iranian man, because he was on an official mission in the northern Kurdish region and the local authorities had knowledge of his visit.

Talabani said Tehran “is threatening to close the borders between Iran and Kurdistan (region),” if the official is not released immediately.

“I express our anger at the US forces' arrest of this civilian visitor without consultation or coordination with the government of Kurdistan,” said the statement posted on the Iraqi presidency website.

“This is an insult and a trespassing on the powers and rights (of the Kurdish region).”

The Iranian citizen was detained Thursday by US forces in the northern city of Sulaymaniyah. US military officials claimed that the man is actually a member of the Quds Force, a special unit of the Islamic Revolutionary Guards Corps.

He was allegedly involved in the smuggling of weapons across the Iraqi border and helped terrorists to enter Iraq.

The administration of the Kurdish autonomous region said the arrest is “illegitimate” and urged the US forces to set the man free, because he is not a member for the Quds Force and is not involved in illegal activities.

Meanwhile, Iranian forces bombed Kurdish areas adjacent to the border early Saturday after a ceasefire which lasted almost a week.

According to Iranian Foreign Ministry spokesman Mohammad-Ali Hosseini, the shelling is targeting extremists and weapons smugglers who are responsible for numerous attacks on Iranian border patrols in northern Iraq.

Despite this official statement, many believe that the military action is actually a retaliation to the detention of the Iranian citizen.