AFP/ Ramadi

Iraqi government and allied forces will launch an offensive aimed at retaking the city of Ramadi from the Islamic State group in the coming days, a spokesman said on Friday.

"Preparations for the Anbar operations are needed because this operation will not be easy," Ahmed al-Assadi, a spokesman for the Popular Mobilisation (Hashed al-Shaabi) forces, said.

The Hashed al-Shaabi are an umbrella for mostly militia and volunteers who joined security forces in Ramadi after they were routed by IS fighters who took over the city on Sunday.

"Daesh (IS) is everywhere in the city, they seized a lot of weapons and we are now focused on acquiring heavier and more modern weapons," Assadi told AFP. "That's important for the liberation of Anbar."

"The operation will not begin in the next few hours but in the coming days," he said.

"It will be a wide operation involving tens of thousands of security forces and Hashed al-Shaabi," said Assadi, who is also a lawmaker from Prime Minister Haider al-Abadi's Dawa party.

Assadi said the most immediate objective was to stop any further advance by the jihadists, who seized more land from the security forces east of Ramadi as recently as Thursday.

A swift counter-attack is key to preventing IS from planting explosive devices across the city, which would make a government advance more risky and complicated.

Iraqi forces have been demanding better weapons to deal with VBIEDs (vehicle-borne improvised explosive devices), the jihadists' weapon of choice.

IS carried out around 30 such attacks over the three days that saw it take control of the capital of Anbar province.

Some of them are huge trucks and bulldozers packed with tonnes of explosives and protected by armoured plates. The enormous blasts they cause can take out several large buildings at once.

The United States announced on Wednesday that it was sending 1,000 AT4 man-portable anti-tank weapons to the Iraqi security forces to help them counter the threat from suicide car bombs.