BAGHDAD — Iraq’s government moved yesterday to restore discipline within the ranks of the security forces, sacking more than 1,300 soldiers and policemen who deserted during recent fighting against Shiite militias in Basra.

At the same time, Iraq’s Cabinet ratcheted up the pressure on anti-American Shiite cleric Muqtada al-Sadr by approving draft legislation barring political parties with militias from participating in upcoming provincial elections.

Mr. Sadr, who heads the country’s biggest militia, the Mahdi Army, has been under intense pressure from Prime Minister al-Maliki, also a Shiite, to disband the Mahdi Army or face political isolation.

Mr. Sadr’s followers are eager to take part in the local elections because they believe they can take power away from rival Shiite parties in the vast, oil-rich Shiite heartland of southern Iraq.

And in a new move to stem the flow of money to armed groups, the government ordered a crackdown on militiamen controlling state-run and private gas stations, refineries, and oil distribution centers.

It is believed that gas stations and distribution centers, especially in eastern Baghdad and some southern provinces, are covertly controlled by Shiite militiamen dominated by the Mahdi Army.

The failure of government forces to capture Basra despite superiority in numbers and firepower was an embarrassment to Mr. Maliki, who ordered the offensive and personally supervised it during the first week.

It also raised questions whether Iraq’s mostly Shiite army and police can confront Shiite militias, including Iranian-backed “special groups,” which the American command now considers the greatest threat to Iraqi democracy with the diminishing influence of Al Qaeda in Iraq.

The national security adviser, Stephen Hadley, said Iran is very active in southern Iraq.

“So we have illegal militia in the southern part of the country that really are acting as criminal elements that are pressing the people down there and, in good measure, as we’ve seen, alienating the Iraqis from Iran,” Mr. Hadley told “Fox News Sunday.”

The Basra offensive — which opened on March 25 — quickly stalled amid strong resistance from the outnumbered militiamen, despite artillery and air support provided by American and British forces. During the attack more than 1,000 security troops — including a full infantry battalion — refused to fight or joined the militias, handing them weapons and vehicles.

American officials have praised Mr. Maliki for the determination he showed in confronting the militias, but they have also said the Basra operation was hastily arranged and badly executed. Critics said it highlighted the Iraqi army’s poor leadership and the low morale among its rank and file.

Washington maintains that as the Iraqi forces increase their capabilities, they will replace American troops providing security in much of the country. But last week, Defense Secretary Gates acknowledged that future American troop withdrawals will go more slowly than had originally been hoped for.

With Al Qaeda’s influence diminishing in Iraq, American troops have much work to do in stemming Iranian support for militias, Mr. Hadley said yesterday. “Iran is very active in the southern part of Iraq. They are training Iraqis in Iran who come into Iraq and attack our forces, Iraqi forces, Iraqi civilians. There are movements of equipment. There’s movements of funds,” Mr. Hadley said. “So we have illegal militia in the southern part of the country that really are acting as criminal elements that are pressing the people down there.”

“Al Qaeda, they’re on the defensive,” he added, citing the illegal militias as an emerging threat. Mr. Maliki, “decided it was time to take control of the situation down there. … He’s had some success. He’s taken control of the port [in Basra]. But there’s more work to do.”