Attacks in Iraq killed eight people and wounded 33 on Wednesday, security officials said, as Baghdad hosted key nuclear talks in its latest effort to emerge from decades of isolation.

Three people were killed and 14 wounded in a shooting and three roadside bombings in Baquba, capital of Diyala province north of the capital, a police lieutenant colonel and Dr Ahmed Ibrahim of Baquba General Hospital said.

And a roadside bomb exploded near a bus carrying Lebanese Shiite pilgrims near Ramadi, capital of Anbar, a Sunni Arab province west of Baghdad, killing three and wounding 10 others, police and medical sources said.

Iraq is home to some of the holiest sites in Shiite Islam, to which hundreds of thousands of pilgrims flock each year. Pilgrims have come under repeated attack by Sunni insurgents, often with bombs.

Two policemen were killed and five wounded in attacks in the northern oil hub of Kirkuk, capital of a province that Kurdish leaders want to incorporate into their autonomous region in northern Iraq, against Baghdad's wishes.

Unknown gunmen attacked the house of a high-ranking police officer, killing a police guard, another high-ranking officer in the Kirkuk police said.

And two roadside bombs targeting a police patrol wounded three policemen in the city, while one policeman was killed and two wounded by a magnetic "sticky bomb" on their vehicle, the officer said.

Despite heightened security measures in and around the Iraqi capital, four people were wounded by a roadside bomb near a Sunni mosque in Al-Yarmuk, west Baghdad, an interior ministry official said.

Thousands of additional Iraqi security personnel have been deployed in areas north, west and south of Baghdad to try to prevent the firing of mortars and rockets into the capital, a security official said.

The official also said without providing figures that additional forces have been deployed at checkpoints in the Iraqi capital, and that searches have been increased.

Major powers were holding talks with Iran in Baghdad on Wednesday, aiming to head off an escalating standoff over Tehran's nuclear programme.

The talks are the latest example of Iraq pushing to host world events and present itself as a relatively stable country no longer rife with violence, but its attempts have so far yielded uneven results.

While violence is down from its peak in 2006 and 2007, attacks remain common, killing 126 people in April, according to official figures.