BAGHDAD -- Insurgents carried out two dramatic ambushes yesterday, killing 11 people, including two American civilians, in a roadside bombing in Basra and an attack on an Iraqi convoy in Baghdad.
Meanwhile, Iraqi officials expressed hope that American hostage Jill Carroll would be released, and kidnappers freed the sister of Iraq's interior minister after holding her hostage for two weeks.
The ambushes, in which gunmen also seized two Kenyan engineers, were part of a surge in violence across the country yesterday that left scores of Iraqis dead.
In the most gruesome development, police said, militants used this week's downing of a US helicopter to carve out a killing field north of Baghdad, slaying more than 40 people on remote roads that Iraqis were forced to use after American troops cordoned off the crash zone.
Thirty people were dragged from their cars yesterday at crude checkpoints erected on unpaved roads and shot dead in farming areas in Nibaei, a town near Dujail, about 50 miles north of Baghdad, said police Lieutenant Qahtan al-Hashmawi.
Since Monday's crash of a US Army AH-64
More than a dozen other Iraqis died yesterday in attacks linked to the insurgency.
With authorities preparing to annouce the results this week of the Dec. 15 election, US and Iraqi officials expect more attacks as religious and ethnic groups jockey for power in the new government.
In the boldest attack, gunmen opened fire on a convoy of the mobile telephone company Iraqna, killing six security guards and three drivers in the Nafaq al-Shurta district of western Baghdad.
Naguib Sawiris, chairman of the Egyptian communications firm that controls Iraqna, said the attackers seized the two Kenyans.
The two American civilians were killed in a roadside bombing in the southern city of Basra. They worked for the Texas-based security company DynCorp and were training Iraqi police. A third American was seriously wounded in the attack, the US Embassy said.
An Associated Press photographer at the scene said two four-wheel-drive vehicles were targeted. The area was surrounded by heavily armed British forces, whose main base in Iraq is in Basra.
The killings occurred as a joint American-Iraqi investigation was underway to find Carroll, a 28-year-old American journalist who was abducted Jan. 7 in Baghdad. The freelance reporter for The Christian Science Monitor was seen in a video aired Tuesday by Al-Jazeera television.
Al-Jazeera said the silent 20-second video included a threat to kill Carroll in 72 hours unless US . authorities release all women detainees in Iraq. US officials said that eight women were in security detention, and that none had been freed as of last night.
Nevertheless, Major General Hussein Kamal, a deputy interior minister, spoke hopefully about prospects for Carroll's release.
''Efforts are continuing to find the American journalist," Kamal said. ''We cannot say more because of the sensitivity of the matter, but, God willing, the end will be positive."
President Bush ignored questions yesterday about what his administration is doing to find Carroll. White House spokesman Scott McClellan said her safe return was a priority for the administration but declined to say more ''because of the sensitivity of the situation."
David Cook, the Washington bureau chief for The Christian Science Monitor, said at a news conference yesterday that Carroll's work has demonstrated she is respectful of Arab culture and people, and that the newspaper has shown it treats different cultures and viewpoints fairly.
He did not answer directly whether the newspaper was involved in any negotiations for her release.
Insurgents in Iraq have kidnapped more than 240 foreigners and killed at least 39 of them. Hundreds more Iraqis have been abducted either by insurgents or gangs seeking ransoms.