US President Barack Obama has touted gains in the campaign against the Islamic State of Iraq and the Levant (ISIL), but cautioned that the group, also known as ISIS, can still direct and inspire damaging attacks.

Speaking after meeting with top aides at the Pentagon, Obama said on Thursday that ISIL will continue to be a threat, highlighting the group's ability to motivate so-called "lone wolf" supporters to launch small-scale attacks that are harder to detect and prevent.

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"What ISIL has figured out is that if they can convince a handful of people, or even one person, to carry out an attack on a subway, or at a parade or some other public venue, and kill scores of people as opposed to thousands of people, it still creates the kinds of fear and concern that elevates their profile," Obama said.

ISIL has claimed responsibility for a number of recent mass killings, including a lorry attack in the French city of Nice last month that left 84 dead, and the nightclub shooting in Orlando, Florida, that killed 49.

While they may not have been directed by the group, the attackers were reportedly inspired by ISIL.

Obama said the US must do a better job disrupting ISIL networks and intercepting the internet messages that can get to individuals and inspire them to act.

"Those networks are more active in Europe than they are here, but we don't know what we don't know, and so it's conceivable that there are some networks here that could be activated," he said.

Warning on overreaction

Obama cautioned against overreacting to such attacks and rejected efforts to demonise Muslims as a way to make the US safer, in a criticism of Donald Trump, the Republican presidential candidate, who has called for a ban on Muslims entering the country.

"If we start making bad decisions, indiscriminately killing civilians, for example, in some of those areas, instituting offensive religious tests on who can enter the country, those kinds of strategies can end up backfiring," Obama said.

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The US is leading a military coalition conducting air strikes against ISIL in Iraq and Syria, where the group seized broad swaths of territory in 2014. 

Since then, the coalition has conducted daily plane and drone strikes - more than 14,000 so far - and worked with local forces on the ground to gradually reclaim the seized territory.

Yet, despite the massive effort, ISIL still holds Mosul, Iraq's second-largest city, and the Syrian city of Raqqa.

"I am pleased with the progress that we've made on the ground in Iraq and Syria," Obama said, but added: "We're far from freeing Mosul and Raqqa."

'Back from the brink'

He also criticised Russia for failing "to take the necessary steps" to try to reduce violence in Syria, saying it was time for Moscow "to show that it is serious" about bringing peace.

Russian President Vladimir Putin has supported Syrian President Bashar al-Assad, offering international cover, military aid and carrying out air strikes in opposition-held areas.

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Obama said the US remains prepared to work with Russia, adding, however, that he was not confident Russia or Putin could be trusted.

"The depravity of the Syrian regime has rightly earned the condemnation of the world," Obama said.

"Russia's direct involvement in these actions over the last several weeks raises very serious questions about their commitment to pulling the situation back from the brink."

Earlier this week, Obama also announced a new front in the war, ordering air strikes against ISIL fighters' positions in the Libyan city of Sirte.

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Source: Al Jazeera and agencies