WASHINGTON — U.S. combat troops may be asked to remain in the troubled northern city of Mosul after June 30 — a key deadline for the removal of such forces from Iraq’s municipalities, members of Rhode Island’s congressional delegation said Wednesday, reporting on their meetings in recent days with U.S. officials in Baghdad.

“There remain difficulties, and they could provoke violence that might require U.S. intervention” in Mosul, Sen. Sheldon Whitehouse said in a telephone interview. “It’s not likely at this point, but it’s not something that can be ruled out.”

Speaking in a separate interview after his own congressional visit to Baghdad, Rep. James R. Langevin said, “I wouldn’t preclude that it might be necessary” to extend the deployment of combat troops in Mosul, “given the al-Qaida presence that is still strong” in Iraq’s second-largest city.

Sen. Jack Reed, who has visited Iraq more than a dozen times since the U.S. invasion in 2003 and is well acquainted with U.S. military leaders, said in Washington that “it’s unclear” whether Iraqi officials will seek an extension of the deadline for removing American troops from Mosul.

“Given the insurgent threat” that has plagued Mosul, Iraqi leaders may seek continued U.S. combat support if they judge that “their local security forces would not be able to handle it alone,” said Reed. He added, however, that with a large American force remaining outside Iraq’s cities, it may be possible for troops not formally designated as combat forces to serve the Iraqi need for support in Mosul.

All three Rhode Island Democrats stressed that any extension of troop withdrawal deadlines would be made at Iraq’s request and in negotiations between the two governments.

The issue is significant because June 30 is the first big date on the schedule for the eventual withdrawal of all American forces from Iraq by the end of 2011. President Obama had campaigned on a promise to remove combat troops within 16 months of his inauguration but loosened his timetable after taking office, essentially accepting the terms of an agreement negotiated late last year between the Iraqi government and the Bush administration. Mr. Obama stressed that the agreement could be changed if security conditions changed.

Some officials have eyed the coming June 30 deadline with concern, noting that insurgents have staged a number of bloody attacks in recent weeks in an apparent effort to disrupt the Iraqi government’s assumption of responsibility for its own security.

Langevin, who expressed reservations about Mr. Obama’s decision when he announced it in February, said in a telephone interview from Bahrain on Wednesday that he now embraces the president’s reasoning.

“I did not want to see a military presence larger than we needed it to be,” Langevin said. But after meeting with troops and their leaders in Iraq this week, he said, “To a person, to a soldier, they are very invested in the mission. They can see the progress,” despite many remaining difficulties, Langevin said.

Langevin said he now agrees with Mr. Obama’s argument that the success of next January’s elections in Iraq is so essential that sufficient U.S. troops must remain to ensure security during that time. “We don’t want to see those elections disrupted by al-Qaida,” Langevin said.

Whitehouse spoke from Bagram Air Base in Afghanistan, his latest stop on a tour of Southwest Asia that began late last week. He is traveling with Sen. Patrick J. Leahy, a Democrat from Vermont.

Whitehouse assessed the progress toward the June 30 milestone after a dinner meeting in Baghdad with Army Gen. Raymond T. Odierno, the commander of the multinational force in Iraq, and Christopher R. Hill, the U.S. ambassador to Iraq. Aside from the possibility of the deadline extension in Mosul, Whitehouse gave a generally upbeat assessment of the situation in Iraq.

Mosul is a multiethnic city, strategically located on trade routes to Syria and Turkey, and close to the semiautonomous Kurdish region of Iraq. Whitehouse noted that Mosul has long struggled with ethnic and religious tensions. In comments earlier this year, Odierno had left open the possibility that Mosul was one city where the deadline for U.S. combat troop withdrawals might have to be renegotiated with Iraqi authorities.

The June 30 deadline is an important milestone on the road to complete withdrawal of U.S. combat forces from Iraq by 2011.