The battle between Islam's two major branches began centuries ago, but it's still affecting Iraq's path to a stable democracy now. The Post's senior national security correspondent, Karen DeYoung, explains. (Davin Coburn/The Washington Post)

Iraq’s Sunni deputy prime minister on Tuesday called on the United States to remain engaged in his embattled country, arguing that it had a “legal and moral responsibility” to help it overcome the latest escalation of violence and instability.

Saleh al-Mutlak, a native of the western Iraqi province where al-Qaeda-linked fighters have made a dramatic comeback in recent weeks, warned that an increase in military aid alone would be futile.

“Weapons alone will not do the job,” Mutlak said during an event at the U.S. Institute of Peace in Washington. “You have to give rights to people who have been demanding them for more than a year.”

Mutlak blamed the escalation of violence in Anbar province and elsewhere in the country on rising sectarian tension, which has soared in the past year as the Shiite-run government has cracked down on a Sunni protest movement.

“We caution everybody who is not complying with [the demonstrators’] demands in a peaceful way,” Mutlak said. “If justice is not delivered, violence will spread all over Iraq, not just Anbar.”

Mutlak has long been a vocal critic of Prime Minister Nouri al-Maliki, a Shiite, and his administration’s security policies, which have alienated and embittered Sunnis. Senior government officials such as Mutlak, who occupy posts reserved for members of political minority factions, have limited say in how the government is run.

Mutlak’s visit comes as Washington and Baghdad are attempting to coordinate efforts to quell the rise in Iraq of an al-Qaeda-linked group that has also emerged as a grave threat to Washington’s interests in Syria. Maliki has urged the Obama administration to speed up the delivery of sophisticated weapons to fight the reconfigured Sunni insurgency that took root in Iraq after the 2003 invasion.

Some members of Congress have raised concerns, saying that Washington’s aid could be used to intensify a crackdown on Sunnis, potentially exacerbating the underlying problem.

Mutlak said Washington must continue to remain invested in Iraq’s success, even though the country’s leaders were unable to negotiate a security deal in 2011 that would have allowed a small contingent of U.S. troops to remain.

“You came to remove Saddam Hussein’s regime,” Mutlak told an audience that included former and current U.S. officials. “Instead of doing that, you destroyed a country.”

Ezzat al-Shebander, a Shiite member of parliament who spoke after Mutlak’s address, said Sunni leaders are not blameless. He said that although Maliki’s government failed to make inroads in Sunni communities to soothe sectarian tensions, Sunni politicians never became effective representatives of their constituents.

“I blame the leaders of the Sunnis because they couldn’t distinguish themselves from the terrorists,” said Shebander, an independent who broke ranks with Maliki’s State of Law party.

Meanwhile, violence continued in Iraq on Tuesday as militants attacked two army tanks and took over a police station near Fallujah, according to the Reuters news agency. Car bombings and other attacks elsewhere in the country left at least 24 dead, according to Reuters.