BAGHDAD  Iraq will ask neighboring countries to help improve its security at a rare regional summit in Baghdad on Saturday that will be attended by the United States.

The Iraqi government will lobby Iran, Syria and other countries to tighten their borders, stop funding sectarian militias and crack down on religious leaders in their countries who encourage violence in Iraq, said Sami Alaskary, a Shiite lawmaker close to Prime Minister Nouri al-Maliki.

The government will oppose any calls by Sunni-dominated countries to abolish Iraq's constitution and start the process over, Alaskary said. Some Arab countries think such a move is necessary for Sunni insurgents to put down their arms and join the government, he said.

"There will be no going back to square one," Alaskary said. "They have to accept that we have a constitution, that this is the army that Iraq has built. There will be no going back."

The Cairo-based Arab League, which includes many Sunni-led countries such as Saudi Arabia and Egypt, said in a statement this week that its delegation to the conference would press for changes to Iraq's constitution. Sixteen countries are expected to send delegates, Alaskary said. Attendees will include all the countries that border Iraq — Syria, Jordan, Saudi Arabia, Iran, Kuwait and Turkey — as well as members of the Arab League, representatives of the Organization of the Islamic Conference, the United States, Britain and others.

Most of the officials will be midlevel diplomats such as deputy foreign ministers, Alaskary said. A second conference, with higher ranking representatives, may be proposed for the near future, he said.

"This is the first small movement in the right direction. It's a long process," said Mithal al-Alusi, an independent Iraqi Sunni lawmaker. "Our neighbors have to understand that they cannot succeed if Iraq's political process fails."

The summit also may result in a rare meeting between the United States and Iran, which have not had formal relations since 1979. Washington has accused Iran of supplying arms to Iraqi militias.

"If we are approached over orange juice by the Syrians or the Iranians to discuss an Iraq-related issue that is germane to this topic — stable, secure, peaceful, democratic Iraq — we are not going to turn and walk away," David Satterfield, the State Department's Iraq coordinator, told reporters.

Iraqi leaders will ask the delegates to send ambassadors back to Iraq, Alaskary said. Many Arab countries pulled envoys from Baghdad after a rash of kidnappings and assassination attempts in 2005.

Contributing: The Associated Press