Iran and Iraq have signed an agreement to boost military cooperation and counter "terrorism and extremism," a deal likely to trigger concerns in the United States.
Iranian news agencies reported that the memorandum of understanding signed by the two countries' defense ministers on July 23 also covers border security, technical and military support, and logistics and training.
Iran and Iraq fought a bloody 1980-88 war during the reign of Iraqi dictator Saddam Hussein. But bilateral ties have improved after Hussein was ousted in 2003 and a government led by Shi'ite Muslims took power in Baghdad. Iran is a predominately Shi'ite nation.
Iran has been supporting a a number of Shiite paramilitary groups and politicians in Iraq in what is seen as Tehran's formidable influence in its neighboring country.
U.S. President Donald Trump, a vocal critic of the 2015 deal with world powers to lift some sanctions on Iran in exchange for curbs on its nuclear program, has taken a hard line on Tehran since he took office in January.
His administration has accused Iran of stoking unrest across the Middle East by supporting terrorist groups in Iraq, Syria, Yemen, and Lebanon.