Updated

President Obama said Monday that the U.S. needs to accelerate the training of Iraqi security forces, on the heels of recent setbacks that have raised doubts about the U.S. approach to fighting the Islamic State.

"They're nimble, and they're aggressive and they're opportunistic," Obama said of ISIS.

The president, speaking in a press conference held on the sidelines of the G-7 summit in Germany, said the key is to get more Iraqi forces trained and equipped, quickly.

"We're reviewing a range of plans for how we might do that, essentially accelerating the number of Iraqi forces that are properly trained and equipped," Obama said, adding he'll share those plans with the American people when the Pentagon presents a finalized proposal to him. Obama said "we do not yet have a complete strategy."

Obama spoke shortly after meeting with Iraqi Prime Minister Haider al-Abadi. The two leaders earlier voiced optimism about taking on the Islamic State despite recent setbacks.

Obama said the U.S. will continue to ramp up training and assistance to Iraqi troops so they can carry out offensive, not just defensive, operations. He cautioned the effort will take time and an inclusive government in Baghdad.

"We have seen successes but we have also seen setbacks," Obama said after meeting with Abadi. He said ISIS "is going to be driven out of Iraq and ultimately it is going to be defeated."

The session with Abadi came just a day after an Iraqi general declared that Iraqi troops, backed by Shiite militias, had recaptured key parts of the northern refinery town of Beiji from the Islamic State. The news was a welcome change of pace for the U.S. after Islamic State militants won a major victory by capturing the city of Ramadi, the capital of Iraq's Anbar province.

Abadi thanked Obama and G-7 members for standing with Iraq against the Islamic State. He said Iraqi troops were winning a number of battles and downplayed Ramadi's loss.

"We lost it only temporarily," he said.

Obama expressed confidence in Abadi's leadership, saying he appeared committed to creating an inclusive government that gave voice to the various factions in Iraq.

Obama addressed a range of other topics during his press conference, including continued Russian intervention in eastern Ukraine. Obama said international sanctions on Russia are having a big impact on the country.

"Russia's actions in Ukraine are hurting Russia and hurting the Russian people," he said, adding that U.S. partners have agreed to keep sanctions in place until Russia lives up to its obligations.

He said the country's forces continue to operate in eastern Ukraine in violation of Ukraine's sovereignty.

He also accused Vladimir Putin of pursuing a "wrongheaded desire to recreate the glories of the Soviet empire."

The Associated Press contributed to this report.