An attack on a diplomatic convoy in Baghdad has injured Poland's ambassador to Iraq and killed three other people. VOA's Jim Randle reports from Irbil in northern Iraq.

Explosions wounded the Polish ambassador, General Edward Pietrzyk, who was taken to a nearby hospital. Doctors there say he will survive.

Poland strongly supported the U.S-led invasion of Iraq in 2003, and has about 1,000 troops in the country.

The attack on the diplomatic convoy is the kind of threat that prompted the U.S. State Department to hire the controversial private security company Blackwater to protect American diplomats.

Tuesday, Blackwater was the subject of a U.S. congressional hearing examining its overall conduct and in particular a chaotic and bloody incident last month in Baghdad that left at least 11 Iraqis dead.

The New York Times newspaper, citing Iraqi investigators, says the actual number of civilian deaths was 17.

Blackwater insists it responded properly to a threat.

Wednesday, Iraq's Prime Minister Nouri al-Maliki said reports reaching him say Blackwater was involved in a series of incidents that left 190 people wounded or dead.

He also said he is closely following the various investigations into the company and the private security industry, but already believes Blackwater should be barred from working in Iraq.

Another Iraqi political controversy heated up Wednesday as Kurdistan's regional government in northern Iraq approved more deals with oil companies.

In a website message, the Kurdistan Regional Government said it approved four contracts for oil exploration and production, along with two new refinery projects. The exploration and related projects will bring a $500 million investment, and the badly-needed refineries will come to about $300 million.

An earlier agreement with the Hunt Oil company drew criticism from rival Sunni and Shi'ite politicians in parliament and was declared "illegal" by Iraqi Oil Minister Hussein al-Shahristani.

The Kurdistan Regional Government has approved an oil law governing its oil industry. But the national parliament in Baghdad has been working on a "hydrocarbon law" that would regulate this crucial industry across the country.

The Kurdistan region of northern Iraq is home to up to a third of Iraq's oil, while the larger Shi'ite area to the south has the bulk of the nation's oil and population. Not much oil has been found in the mostly Sunni areas in the center and west.