A mortar attack targeting Shiite worshippers killed three people in eastern Baghdad on Friday, and authorities were investigating whether attackers set off explosions that sparked an early morning fire at a nightclub that left six dead.

Friday's violence was the first in Iraq after several days of calm during the three-day holiday earlier this week marking the end of the holy month of Ramadan. Before the Eid al-Fitr holiday, more than 200 people were killed in August violence across the country.

In the mortar attack, police said an explosive shell landed near a mosque shortly after the start of Friday prayers in the Shiite district of Sadr City. The sermon there was delivered by a backer of the Shiite firebrand cleric Muqtada al-Sadr. Eight people were wounded, including the preacher, Nassir al-Saadi.

Sunni insurgents frequently attack Shiites in an attempt to revive sectarian fighting and undermine the Shiite-dominated government.

In a separate incident, two police officers said attackers set off a bomb and then threw grenades from a speeding car at the Qasr al-Sharq, or "Palace of the East," hotel in Baghdad's downtown Karradah district early Friday. The hotel includes a hall that witnesses say is used as a nightclub.

Six people died and 12 were injured when a fire erupted inside the entryway of the hotel.

Other security officials, including Dhia al-Wakil, spokesman for the operations command in Baghdad, said authorities were still trying to determine if bombs set off the blaze.

"We do not want to speculate. We should wait for the results of the investigation," he said.

Hospital officials, who confirmed the casualties in both the mortar attack and the hotel incident, said victims in the hotel suffered injuries that included smoke inhalation as well as shrapnel wounds. The officials and most police officials spoke on condition of anonymity because they were not authorized to speak to journalists.

Nabil Sattar said he saw the fire at the hotel and rushed to help.

"We rescued some people who were suffering from suffocation, but others were forced to jump from the balconies in order to escape the smoke," he said.

One police officer investigating the fire, who declined to be named, blamed it on an intentional attack by Muslim extremists.

"They have radical ideas that reject alcohol, live music and dancing," he said.

Nightclubs are a form of entertainment considered taboo by conservative Muslims.

Iraqi officials had warned of large-scale attacks during the Islamic holiday, and security measures were tightened in all over the country, especially in the capital. Many public sector employees were given the whole week off, filling parks, restaurants and cafes late into the night.


Associated Press writer Adam Schreck in Baghdad contributed to this report.