Fierce fighting between Iraqi forces and rebel groups including al-Qaida was reported near Falluja on Tuesday, 24 hours after the US agreed to speed up arms sales to the government in Baghdad.

The standoff between the Iraqi army and the insurgents poses a dilemma for the Obama administration, torn between distaste for Iraqi prime minister Nouri al-Maliki's sectarian approach to politics and a resurgence of al-Qaida in the country.

The Associated Press news agency quoted Dhari al-Rishawi, the governor of Anbar province, which includes Falluja and Ramadi, as saying clashes on Tuesday took place 12 miles west of Falluja. The ministry of defence claimed to have killed 25 al-Qaida militants in an air strike in the province.

The Iraqi government urged tribal leaders to turn on the insurgents and drive them out of the city. The insurgents vowed to stay and fight. "They'll only enter Falluja over our dead bodies," one of them, Khamis al-Issawi, said in a phone interview with Reuters.

Security officials and tribal leaders said Maliki had agreed to hold off an offensive to give people in Falluja time to push the militants out. But it is not clear how long they have before troops storm the town.

"We've done our part of the deal. Now they [tribal leaders] should do theirs. If not, a quick offensive is coming," an Iraqi special forces officer told Reuters.

Iraq's US-equipped armed forces have killed dozens of militants in recent days in shelling and air strikes, officials say. The scale of casualties among civilians, security forces and tribal fighters is not clear.

The takeover of the centre of Falluja and the outskirts of Ramadi by Sunni protesters, including the al-Qaida grouping Islamic State of Iraq and Syria (Isis), is of especial symbolic importance for Americans, both cities being the scene of bloody fighting during the US-led occupation.

"It is profoundly embarrassing for the US. These are iconic cities that were taken at enormous cost to the US. It is incredibly embarrassing to see them taken over by Islamists," said Shashank Joshi, a Middle East security specialist at the London-based Royal United Services Institute.

The US announced on Monday it is to accelerate military sales to Iraq, including 10 ScanEagle drones and 48 Raven drones. It said the drones were purely for surveillance. A consignment of 75 Hellfire missiles arrived in Iraq last week.

The CIA, which retained a presence in Iraq after the 2011 US troop withdrawal, is reported to be involved in helping with co-ordination of intelligence as well as targeting Hellfire missiles. In addition, there are 200 US military advisers left after the withdrawal.

While the worry for the US is that it may face an expansion of al-Qaida in both Iraq and Syria, Toby Dodge, professor of international relations at the London School of Economics and a regular visitor to Iraq, predicted that both Iraqi and Syrian governments would gain the upper hand in the battle with al-Qaida.

There was close co-operation between al-Qaida in Iraq and Syria, he said, but "both the Syrian and Iraqi governments are strong enough to beat al-Qaida militarily".

The Iraqi military is 933,000-strong, accounting for 8% of the country's workforce and 12% of the adult male population.

Although the US had a tough fight in Falluja in 2004, razing huge parts of the city to the ground, Dodge said that al-Qaida is much weaker today, with nothing like the level of support it had during the US occupation. Intelligence estimates put membership of al-Qaida in Iraq at 3,000, up from 1,000 in 2011.

Joshi warned that al-Qaida was only one element in a coalition of groups opposed to the Maliki government. "What we are seeing in Anbar is bigger than just al-Qaida. What were are seeing includes a protest movement and armed tribes."

Maliki, a Shia, is accused of creating the crisis by pursuing a sectarian policy that has seen Sunnis ousted from prominent government positions.

The US Congress is blocking the sale of Apache helicopter gunships to the Iraqi government amid concerns they might be used for sectarian repression, but the White House, worried about al-Qaida, backs the sale.

The problem facing the White House in the coming weeks is how to support the Iraqi government in Falluja and Ramadi without encouraging Maliki to think he does not have to find a political solution.

"The more you encourage him to feel there is a purely military solution, the harder it is to persuade him to compromise with Sunni opponents," Joshi said.

In a newly published report, Iraq in Crisis, Anthony Cordesman and Sam Khazai, for the Washington-based Centre for Strategic International Studies, are pessimistic in their conclusion.

"No outside power can change the situation. Given Iraq's current political divisions and leadership, the most the US and other outside states can do is choose between bad alternatives and pursue the least bad options," they say. © Guardian News and Media 2014