WASHINGTON - U.S. President Donald Trump welcomed Iraq's prime minister and a large Iraqi delegation to the White House on Monday, for talks aimed at further coordinating efforts to defeat Islamic State extremists in northern Iraq.

As the meeting opened, Trump praised Iraqi government efforts to face down the extremist group, and then told Prime Minister Haider al-Abadi that he hoped to discuss the “vacuum” created when IS fighters seized control of large swaths of northern and western Iraq in 2014.

“We will figure something out. Our main thrust is we have to get rid of ISIS,” Trump said, using an acronym for Islamic State.

Trump also lamented the 2011 withdrawal of U.S. forces from Mosul and the rest of Iraq — a decision made in 2008 and later implemented by President Barack Obama after Iraqi and U.S. negotiators could not agree on details for extending an immunity agreement covering U.S. forces and U.S. contractors.

“Certainly we shouldn't have left, we should never, ever have left,” Trump said, in comments that followed his suggesting that “perhaps we shouldn't have gone in” in the first place.

Trump also raised the issue of Iran and its nuclear ambitions, questioning why his predecessor, Barack Obama, signed a nuclear agreement with Tehran that lifted a longstanding Western trade embargo against the Islamic Republic.

For his part, Abadi told Trump that his government commands “the strongest counterterrorism forces. But we are looking forward to more cooperation between us and the U.S.,” he said.

Prime Minister of Iraq Haider al-Abadi shakes hand Prime Minister of Iraq Haider al-Abadi shakes hands with Nancy Lindborg, president of the United States Institute of Peace, after speaking at the institute in Washington, March 20, 2017. Prime Minister of Iraq Haider al-Abadi shakes hands with Nancy Lindborg, president of the United States Institute of Peace, after speaking at the institute in Washington, March 20, 2017.

Abadi addresses peace institute

Later Monday, Abadi addressed an audience at the independent U.S. Institute of Peace, where he praised the Trump administration for supporting Iraqi initiatives aimed at crushing Islamic State and rebuilding Iraqi cities.

“We have been given assurances that the support will not only continue but will accelerate. I think we are happy with the [White House] meeting ... and we're looking forward to meeting with Congress and others,” he said.

He also said a growing number of U.S. companies have shown interest in boosting cooperation in trade, commerce, energy and education. “And we're meeting [with] them today,” he said.

Coalition set to meet Wednesday

The Iraqi leader's first meeting with Trump comes as the U.S. administration prepares for a 68-nation meeting later this week of the Global Coalition working to defeat Islamic State. The gathering at the State Department is the first meeting of the full coalition since December 2014.

A U.S. statement said the agenda will target multiple objectives, including counterterrorist financing and the stabilization of areas already liberated from IS control.

The conference also comes as an Iraqi military coalition presses its offensive against Islamic State in the northern Iraqi city of Mosul.

During a 2016 visit to Washington, Abadi sought additional financial and military support for the daunting task of rebuilding Iraqi cities ravaged by 14 years of war. He also sought aid to counter a massive humanitarian crisis spawned by the fighting, which has displaced more than 4 million people.

Iraqi Prime Minister Haider al-Abadi speaks during Iraqi Prime Minister Haider al-Abadi speaks during a meeting with President Donald Trump in the Cabinet Room of the White House, March 20, 2017. Iraqi Prime Minister Haider al-Abadi speaks during a meeting with President Donald Trump in the Cabinet Room of the White House, March 20, 2017.

Abadi seeking reconstruction aid

Abadi was expected to renew those calls during his visit, which coincides with an ongoing civilian exodus from Mosul, as government forces advance on fortified IS positions in Mosul's Old City.

But the extent of Washington's commitment to providing such aid remains unclear, shrouded by proposals to cut as much as 30 percent in funding from the budgets of the State Department and the U.S. Agency for International Development. Both entities focus significantly on international peacekeeping initiatives and development programs.