LONDON — The U.S. and its allies sought to put a good face on the coalition’s deliberate campaign to roll back the Islamic State in Iraq and Syria on Thursday, boasting of having killed thousands of militants while acknowledging that ousting the group from key cities remains a distant aspiration.

Speaking alongside the British foreign minister and Iraqi prime minister, Secretary of State John Kerry said nearly 2,000 airstrikes had arrested the Islamic State’s momentum, squeezed its finances, killed “in the single digit” thousands of fighters and eliminated half of the group’s leadership.

Kerry’s remarks came after Iraqi Prime Minister Haider al-Abadi said a day before the London meeting that the U.S. and its partners weren’t moving fast enough in supplying Iraq with weapons. “There is a lot being said and spoken, but very little on the ground,” al-Abadi said.

Kerry, British Foreign Secretary Philip Hammond and al-Abadi spoke after meeting with officials from 21 countries to take stock, as Kerry put it, of progress made by the often-divided coalition against Islamic State militants who control a third of Iraqi and Syrian territory.

Al-Abadi took a more conciliatory tone after Thursday’s meeting. “I have asked people for more support and I think my call didn’t go unnoticed,” he said.

Kerry said the Islamic State had been “definitively” halted in Iraq, even though the strategic city of Mosul remains in IS control. Kerry said Iraqi ground troops had retaken 270 square miles of territory and deprived the militants of the use of 200 oil and gas facilities.

But he acknowledged that “we have decided there are things we can do more of,” including beefing up efforts to halt foreign fighters, curb the Islamic State’s finances and publicly counter the group’s social media presence. U.S. intelligence officials say the pace of foreigners traveling to fight with the Islamic State group has not slowed, and that the group’s ideology is spreading.