US President Barack Obama has defended his strategy to combat Islamic State (Isis) in Syria and Iraq in the wake of the deadly terror attacks in Paris. Speaking at the G20 meeting in Antalya, Turkey, he said a US-led ground invasion of Syria would be a "mistake" and accused critics of his strategy of lacking a "specific plan" to combat the militant group.

Last month the Pentagon said it would deploy less than 50 special operations forces to Syria to advise and assist moderate rebels combating Isis, but the administration has come under pressure to do more in the wake of the attacks in the French capital which killed 129 people on 13 November.

Obama asserted that air strikes by the US-led coalition have been effective in taking out key members of the Isis leadership and defended his use of the term "contained" to refer to the threat of the jihadist group.

"When I said that we are containing their spread in Iraq and Syria – in fact, they control less territory than they did last year," he was quoted as saying by the Guardian newspaper.

"The more we shrink that territory, the less they can pretend they are somehow a functioning state and the more it becomes apparent that they are simply a network of brutal killers. That allows us to reduce the flow of foreign fighters, which over time will lessen the numbers of terrorists who can potentially carry out terrible acts like they did in Paris."

'Unconventional warfare'

The US commander-in-chief cautioned against a knee-jerk reaction to the violence in Paris, which he described as "a terrible setback. There will be an intensification of the strategy that we put forward, but the strategy that we put forward is the strategy that is ultimately going to work," he stressed.

"It is not just my view, but the view of my closest military and civilian advisers, that [launching a ground invasion] would be a mistake. Our goals here have to be aggressive ... but also recognise this is not conventional warfare.

"We play into the Isil (Isis) narrative when we act as if they are a state and we use routine military tactics that are designed to fight a state that is attacking another state. That's not what's going on here."

The US-led coalition's year-long bombing campaign in Syria has been complicated by Russia's entry into the four-year conflict, backing Syrian President Bashar al-Assad, while Iran is also an active backer of the Syrian regime.

Vladimir Putin & Barack Obama
Obama discussed a co-ordinated response to the Syrian crisis with Russian President Vladimir Putin Reuters

Obama held a 30-minute meeting with Russian President Vladimir Putin on the sidelines of the G20 summit, where the leaders discussed a co-ordinated response to the crisis in Syria. The Syrian civil war has left 250,000 people dead and forced 11 million to flee their homes, sparking a refugee crisis in the Middle East and Europe.

'Not interested in posturing'

Obama added: "It's best that we don't shoot first and aim later. If folks want to pop off and have opinions about what they want to do, present a specific plan. What I am not interested in doing is posing, or pursuing some notion of American leadership or America winning or whatever other slogans they come up with ... I'm too busy for that.

"What I do not do is to take actions either because it is going to work politically or somehow make America look tough, or make me look tough." he added.