By Kareem Raheem
BAGHDAD (Reuters) - At least seven bombs battered Shi'ite and Sunni Muslim neighborhoods across Baghdad on Thursday, killing at least 16 more people in the worst wave of sectarian violence since civil war five years ago.
The bloodletting reflects increasing conflict between Iraq's majority Shi'ite leadership and the Sunni minority, many of whom feel unfairly treated since the 2003 fall of strongman Saddam Hussein, a Sunni.
Civil war in Syria between Sunni rebels and President Bashar al-Assad, whose Alawite sect derives from Shi'ite Islam, has aggravated the strife in Iraq. Sunni and Shi'ite Iraqis have been crossing the border to fight on opposing sides in Syria.
No group claimed responsibility for Thursday's attacks, but Sunni Islamist insurgents and al Qaeda's Iraqi wing have increased their operations since the beginning of the year as part of a campaign to exacerbate inter-communal tensions.
A car bomb exploded in the mainly Sunni district of Binoog in north Baghdad, killing at least four people. Throughout Thursday, six other bombs killed 12 people in mainly Shi'ite and Sunni districts of the capital, police said.
A further seven people, including three policemen, were killed in clashes between gunmen and security forces in the northern city of Mosul, officials said.
The Sunni governors of Anbar and Salahuddin provinces both escaped assassination attempts unhurt on Thursday when their convoys were attacked with car bombs. The two men have been cooperating with Shi'ite Prime Minister Nuri al-Maliki in an effort to defuse Sunni discontent.
Attempts to ease the political crisis have been hampered by deep divisions among Sunni leaders. Moderates who favor negotiations have sometimes been attacked by hardliners and insurgents who oppose Maliki.
"Systemic violence is ready to explode at any moment if all Iraqi leaders do not engage immediately to pull the country out of this mayhem," the United Nations envoy to Iraq Martin Kobler said in a statement.
The surge in violence began in April when Iraqi forces raided a Sunni protest camp in the northern town of Hawija, angering Sunni leaders and triggering clashes that spread across the country.
More than 1,100 people have been killed since then, raising the risk of a relapse into outright sectarian warfare of the kind that killed thousands of people in 2006-2007.
Security officials blame Sunni Islamists and al Qaeda's local wing, the Islamic State of Iraq, for most of the violence.
Thousands of Sunnis have protested weekly in the streets in western provinces since December, and the country's government - split among Shi'ite, Sunni and ethnic Kurds - is locked in disputes over how to share power.
(Additional reporting by Suadad al-Salhy in Baghdad and a reporter in Mosul; Writing by Patrick Markey; Editing by Andrew Roche)