Iran has been careful not to flaunt its links to Iraqi Shias. For two decades, Iran has provided refuge, weapons and financial support for Iraqi Shia Arabs. During the 1991 Shia uprising, Iran allowed these armed Iraqi exile groups to cross into Iraq, but Saddam's forces defeated them. Neither the US nor Iran wanted to anger the rest of the Arab world by openly supporting the rebellion against Saddam. Iran has always maintained a large espionage network in Iraq, and still supports some Iraqi exiles. But Iran continues to deny any involvement in the internal affairs of Iraq, despite mounting evidence contradicting this. Recently, long time American ally, Iraqi exile leader Ahmed Chalabi, was discovered to be a spy for Iran. There are many others. Some do it for money, but many Iraqi Shia see Iran, a largely Shia nation, as a more reliable ally than the Sunni Arab nations to the south and west, and the Sunni Turks to the north.