WASHINGTON - The US government is directly supplying weapons to Peshmerga fighters from Iraq's semi-autonomous Kurdish region to help them fight Sunni militants, in a deepening of America's military involvement in Iraq, US government sources said on Monday.

The weapons shipments to Arbil, capital of Iraqi Kurdistan, come as Kurdish fighters struggle to stem advances by militants from the Islamic State, an al Qaeda offshoot.

US government sources said the weapons were supplied by the Central Intelligence Agency but that the Department of Defense may soon start arming the Kurdish fighters, who regained control of two strategic towns in northern Iraq on Sunday with help from US airstrikes.

Weapons have also been shipped in three deliveries from the Iraqi government in Baghdad to Arbil, consisting mostly of AK-47 assault rifles and ammunition, the US officials said, declining to specify when they began.

Until recently, the US government refrained from directly supplying weapons to the Kurds, leaving that to the Shi'ite-dominated Iraqi government despite Kurdish complaints that Baghdad had deprived them of weapons and financial support.

US President Barack Obama has faced growing criticism for being reluctant or too slow to intervene in thorny foreign policy issues which have piled up under his watch, including the dramatic rise of the Islamic State, which has seized control of large swathes of land in the north and west of OPEC member Iraq.

A senior US defense official acknowledged that the US was providing arms and ammunition needed by the Kurds but said it was not coming from the Department of Defense.

Just last week Washington launched its first military action in Iraq since pulling its troops out in 2011. US warplanes bombed Sunni insurgents from the Islamic State, who have marched through northern and western Iraq since June.

Washington says it is taking limited action to protect the Kurdish autonomous region and prevent what Obama called a potential "genocide" of religious minorities targeted by the militants.

The militants made new gains against Kurdish forces despite three days of US airstrikes, while Baghdad, long braced for the Sunni fighters to attack, was now tensing for possible clashes between forces loyal to Prime Minister Nuri al-Maliki and those of his rivals after Iraq's president named a new prime minister on Monday.

Obama says a more inclusive government in Baghdad is a precondition for more aggressive US military support against the Islamic State. He has rejected calls in some quarters for a return of US ground troops, apart from several hundred military advisors sent in June.

The Islamic State, which sees Shi'ites as heretics who deserve to be killed, has ruthlessly moved through one town after another, using tanks and heavy weapons it seized from soldiers who have fled in their thousands.

On Monday, police said the militants had seized the town of Jalawla, 115 km (70 miles) northeast of Baghdad, after driving out the Kurds' Peshmerga forces.

Washington and its European allies are considering requests for more direct military aid from the Kurds, who have themselves differed with Maliki over the division of oil resources and who took advantage of the Islamists' advance to expand their territory.

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