Iran opened on Monday five border crossing points with Kurdish-run northern Iraq, closed last month by Tehran to protest the U.S. detention of an Iranian here, an Iraqi Kurdish official said.

Jamal Abdullah, spokesman for the Kurdish regional government in northern Iraq, expressed relief that the crossings reopened at 9 a.m. Monday and added that the decision to reopen them followed a visit by a Kurdish delegation to Iran three days ago.

Iran closed the border with the Kurdish northern Iraq on Sept. 24 following the arrest of Mahmoud Farhadi, who was taken into custody four days earlier by U.S. troops in the Iraqi Kurdish city of Sulaimaniyah

The U.S. military said the arrested Iranian was a member of the Quds Force, a branch of the Iranian Revolutionary Guards alleged to smuggle weapons to Shiite extremists in Iraq.

The Iraqi government has asked the U.S. Embassy in Baghdad to release the man, saying he was in the country on official business.

Last week, Iraq's Foreign Minister Hoshyar Zebari, a Kurd, complained that Iran was punishing the Kurdish region for something the Kurdish authorities were not responsible for — the Iranian's arrest. The Kurdish region relies heavily on commerce with Iran and economic ties between the two are strong.

But U.S. officials have complained the porous boundary is a transit route for foreign fighters and weapons into Iraq.

"Reopening borders will have its good results of economical interests for both countries," Abdullah said, adding it was up to Tehran and Baghdad to "prevent gunmen from having access to either side of border."

Hundreds of cargo trucks had lined up on the Iraqi side of the border Sunday, when Iran's official news agency IRNA had said the crossing would reopen.

Farhadi's arrest has raised U.S.-Iran tensions, already taxed over Tehran's controversial nuclear program and the January arrest by U.S. troops of five other Iranians in Irbil, northern Iraq, for alleged links to the Quds force.

Farhadi and the five Iranians remain in U.S. custody.