BAGHDAD, Iraq (AP) – The U.S. Central Command chief confronted Iraq’s prime minister on Monday over how Iraqi forces would halt raging violence and signaled a possible prelude to shifts in American policy on engaging Iran and Syria.

The meeting came as sectarian attacks killed at least 91 people throughout Iraq, 46 of them showing signs of torture. The U.S. military announced the deaths of four additional American soldiers.

Gen. John Abizaid, commander of all U.S. forces in the Middle East, sternly warned Prime Minister Nouri al-Maliki that he must disband Shiite militias and give the United States proof that they were disarmed, according to senior Iraqi government officials with knowledge of what the two men discussed.

Beyond that, Abizaid asked the Iraqi leader to give the U.S. military a firm timetable for when Iraq’s security forces could take full control of the country, the officials said on condition of anonymity because of the sensitive nature of the talks.

Al-Maliki has been pressing the U.S. to move more quickly to hand security affairs over to his army, claiming it could crush violence in the country within six months. Abizaid apparently called al-Maliki’s bluff by asking the prime minister to give a detailed explanation of how he would do that. The top U.S. commander in Iraq, Gen. George Casey, recently said it would take 12 to 18 months before Iraqi security forces were ready to control the whole country with some U.S. backup.

The U.S. did not respond to requests for comment on Monday’s meeting.

But a brief statement by the Iraqi government said Abizaid told al-Maliki he had come to “reaffirm President Bush’s commitment” to success in this country. It also said the two discussed the “effect of neighboring countries on the security situation in Iraq,” a clear reference to Iran and Syria.

That was particularly significant given that al-Maliki had said only a day earlier that he was ready to take “five steps” toward Syria if it took one in Iraq’s direction.

After more than two decades of virtual estrangement between Damascus and Baghdad, the al-Maliki government has invited Syrian Foreign Minister Walid Moallem to visit and he accepted, although no date had been set.

What’s more, the American blue-ribbon bipartisan commission trying to devise a new course for the war in Iraq, which met with President Bush and other White House officials Monday, was widely expected to recommend that the administration engage Iraq’s neighbors in a bid to tamp down violence.

The Iraq Study Group plans to announce its recommendations to Bush and Congress by year’s end.

The reference to Iraq’s neighbors coincided with a call by British Prime Minister Tony Blair for Iran and Syria to help stem bloodshed in Iraq and to join efforts to stabilize the Middle East.

In a major foreign policy speech Monday night, Blair warned there would be no incentives or concessions for doing so and that any failure to assist would lead to international isolation for the two countries.

Blair was to speak with the Iraq Study Group by video-link Tuesday. Britain has been the Bush administration’s key ally in the Iraq war and has about 7,000 forces in the country.

The Syrian ambassador to Washington affirmed a readiness to work with the United States.

“We in Syria believe that engagement with the United States on Iraq can help a lot, because we believe that we need to stabilize the situation in Iraq and support the political process there,” Imad Moustapha told the British Broadcasting Corp.

Both Washington and Baghdad charge Syria with doing too little to prevent foreign fighters, especially al-Qaida operatives, from crossing its border into Iraq. Beyond that, top members of Saddam Hussein’s former regime have found safe haven in Syria, where they have operated freely in helping fund and organize the Sunni insurgency that is responsible for the vast majority of U.S. deaths in Iraq.

As for Iran, many of the key figures in Iraq’s now-dominant Shiite hierarchy spent years in exile there during Saddam’s rule. One Shiite militia was trained by Iran’s Revolutionary Guard. Iran is known to fund that militia and one loyal to radical Shiite cleric Muqtada al-Sadr. Both are believed deeply involved in the sectarian killing that is tipping Iraq toward all-out civil war.

Abizaid was the third top U.S. official to visit Iraq since Oct. 30, and the meeting comes a day after al-Maliki promised to shake up his government in a bid to end the sectarian slaughter.

National Security Adviser Stephen Hadley was first to visit, followed five days later by U.S. National Intelligence Director John Negroponte.

Before Abizaid pushed the same theme, Negroponte also demanded that al-Maliki disband militias by year’s end _ but was met with a flat rejection. Al-Maliki told Negroponte such a move would be political suicide. Al-Maliki, a Shiite, relies heavily on two major Shiite political groups which run the heavily armed militias.

In Monday’s meeting, the government said, Abizaid “emphasized the multinational forces’ commitment to training Iraqi security forces to handle security in all Iraqi provinces.”

Responding to statements by al-Maliki that the United States should move more quickly to hand security affairs over to his army, Abizaid asked for “proof that Iraqi security forces were capable of controlling the security situation in order for us to give you more powers as the commander in chief,” according to the Iraqi government officials.

Such a move seemed distant Monday as at least 91 more Iraqis died violently, and the U.S. military reported the deaths of four more soldiers. The American deaths raised to 2,852 the number of U.S. forces who have died since the U.S. invasion in March 2003. So far this month, 34 American service members have been killed or died in Iraq.

The bomb that killed 20 was planted on a bus in the northeast Baghdad Shaab neighborhood and detonated shortly after noon at a major intersection, police said. Sunni insurgents have frequently targeted Shiite bus passengers in the sectarian reprisal killings that are tearing at the fabric of Iraqi society.

Hours earlier, Mohammed al-Ban, a cameraman for Iraq’s independent Al-Sharqiyah satellite television, was gunned down leaving his home in the northern city of Mosul. His wife was wounded, police said.

Al-Ban is the second Al-Sharqiyah journalist to be killed in recent weeks. Anchorwoman Leqaa Abdul Razzaq was fatally shot last month in Baghdad.

At least 89 journalists have been killed in Iraq since hostilities began in March 2003, according to an Associated Press count based on statistics kept by the New York-based Committee to Protect Journalists. Thirty-five other media employees, including drivers, interpreters and guards, have been killed, all but one of them Iraqi.

Gunmen mowed down at least 24 other people, including a city councilman and a Sunni sheik, in executions and assassinations around Iraq. At least 46 bodies were also found shot and with signs of torture.

AP correspondents Qassim Abdul-Zahra and Bassem Mroue contributed to this report.