State run television in Iraq described a buildup of tanks along with other military vehicles in al-Habbaniyah camp. Islamic State fighters are reportedly on their way towards the base.
The government of Iraq called for help from the militias, which are backed by Iran after its military was routed and quickly fled for safety. Nearly 500 people were killed in the city, which is only 70 miles to the west of Baghdad.
An Anbar provincial council member said that Shia forces were now at Habbaniya, which is only 12 miles from Ramadi and were on standby.
The council in a prepared statement said close to 3,000 Shia fighters arrived to help liberate Ramadi from the Islamic State group.
However, the IS militants were also advancing from the city of Ramadi to al-Khalidiyah which is close to Habbaniyah base, said a statement from the IS.
Ramadi falling to IS was a disaster for the army of Iraq and its government. After the recapturing of another capital of a province, Tikrit, the end of March, the Iraq government announced it would do the same to liberate Anbar province and travel to Ramadi to start its campaign.
However, now the city has fallen to the IS as well as the military command for the entire province.
Now the government and the mostly Sunni provincial council must do what they did not want to and that is call in the Shia militias that are supported by Iran and were instrumental in helping recapture Tikrit.
The Shia will play the leading role in liberating Ramadi if Iraq wants it recaptured. One big question is if the U.S.-led coalition will bomb to support the recapture of Ramadi, which helps to spread the penetration of Iran and its control inside Iraq.
The United States said it was confident that Ramadi could be recaptured from IS.