A series of huge bombings in northern Iraq have triggered fiery accusations of blame between Arabs and Kurds, escalating a dispute over land and oil that has played into the hands of a resurgent Al Qaeda.

Truck bombings and suicide attacks have killed scores of people and caused enormous destruction in northern Iraq near the troubled city of Mosul this month, which lies close to territory disputed by Iraq's Arab majority and minority ethnic Kurds.

Khisro Goran, a senior Kurdish politician in Mosul, said the mainly Sunni Arab Al-Hadba group that won control of the local council this year had to take the blame for "inciting" Arab nationalists and armed groups like Al Qaeda to attack Kurds.

"They facilitate access for the suicide bombers," he added.

Al-Hadba won seats with an anti-Kurdish election campaign earlier this year. Its leaders reject Kurdish accusations.

The Kurdistan Regional Government, which governs a largely autonomous enclave nearby in northern Iraq, accused Arab officials in Mosul of trying to "ethnically cleanse" the region of Kurds.

The Sunni Arab governor of Nineveh province, of which Mosul is the capital, in turn blames Kurdish Peshmerga soldiers for security breaches. Peshmerga are deployed near Kurdistan's borders, including areas around Mosul.

"There have been Peshmerga forces in these areas for a long time, and (the bombings) have given them legitimacy to remain to protect Kurdistan only. They are not concerned with what happens in Nineveh," governor Atheel al-Nujaifi said.

The boundary between Kurdistan and the rest of Iraq is blurred due to seemingly intractable disputes over territory and oil between Iraq's Arabs, now led by a Shi'ite Muslim government, and Kurds. Kurds see parts of northern Iraq as their ancestral homeland, and want them folded into Kurdistan.

Arabs and Turkmen in those areas fear Kurdish hegemony. The tensions have triggered standoffs between the Peshmerga and Iraqi security forces that have come close to war.

The deep mistrust and lack of security coordination between the two sides has allowed Al Qaeda and other militants to thrive, as has northern Iraq's remote and mountainous terrain, where such groups can hide out between attacks.

The pullback of US troops from Iraqi cities at the end of June may also have given Al Qaeda more breathing room.

The targets in a string of blasts this month appear carefully chosen to fan Kurd-Arab tensions, driving a wedge deeper between them just as politicians are talking about broad coalitions to contest parliamentary polls due in January.

A suicide car bomber on Aug 7 targeted Shi'ite Muslims leaving a mosque near Mosul. Then a double truck bombing on Aug 10 targeted a Shi'ite Muslim community of Kurdish origin, also near Mosul. On Aug 13 two suicide bombers struck the Yazidi community, a pre-Islamic Kurdish sect, again near Mosul.

The fact that none of the blasts targeted Sunnis has cast the spotlight of Kurdish suspicion on Sunni Arab Al-Hadba.

Al Qaeda and other Sunni Islamist groups often target non-Sunni Arabs, mainly Shi'ites, but also Kurds and Christians.

However, Arab officials point to the fact that the blasts happened in disputed areas with relatively few Iraqi forces due to the presence of Peshmerga troops. There have not been major bombings in Mosul itself, which Iraqi forces control.

Meanwhile, one outcome seems to be Al Qaeda's resurgence. "Political differences have left security breaches. There are disputed areas in which Iraqi security forces do not enter, so they are exploited by Al Qaeda and other terrorists," said Iraqi Minister of State for National Security Shirwan Al-Waeli, who had just returned from a fact-finding trip to Mosul.

The US military this month said Al Qaeda's capabilities had grown in northern Iraq, and the Pentagon said it was "very nervous" about Kurd-Arab tensions.