The air campaign against the ISIS group has made progress in degrading the jihadist organisation but will not be enough without local boots on the ground, the US Air Force secretary said on Tuesday.

The comments from Deborah Lee James come just days after Pentagon chief Ashton Carter raised the possibility of deploying additional US special forces personnel to Syria if more partners can be found among local forces on the ground. “Air power is extremely important. It can do a lot but it can’t do everything,” Ms James said.

“Ultimately it cannot occupy territory and very importantly it cannot govern territory,” she told reporters at the Dubai Airshow. “This is where we need to have boots on the ground. We do need to have ground forces in this campaign.” Ms James cited the “Iraqi Army, the Free Syrians and the Kurds” as forces to support in the fight against ISIS.

A US-led coalition has been carrying out airstrikes against ISIS in Iraq and Syria for more than a year in a campaign that has seen the jihadists lose some territory but also make new gains.

The White House announced on October 30 that US President Barack Obama had authorised the first sustained deployment of “fewer than 50” special force personnel to Syria, reversing a longstanding refusal to put US boots on the ground. And in an interview on Sunday, the Pentagon chief said that more US troops could “absolutely” be deployed to Syria if Washington identifies more “capable local forces” as partners in the fight against ISIS.

While US troops are believed to have carried out covert missions in Syria before, they had not previously been deployed there on a continuous basis.

Meanwhile, Russia’s foreign minister Sergei Lavrov on Monday said countries will hold “enlarged” talks on the Syrian conflict soon, accu-sing some of trying to evade negotiations. Speaking in the capital of Armenia, Mr Lavrov said the list of players attempting to find common ground over the conflict that killed 250,000 people has grown since last month’s unprecedented talks in Vienna. “There will be another meeting in the nearest future in an enlarged format... That is about 20 countries and organisations,” he said.

The Arab League and the Organisation of Islamic Cooperation will join the table, which includes the United States, France and Iran, to continue discussing the possibilities of a political settlement for Syria. Mr Lavrov added that making progress ahead of the next meeting on the Syrian conflict is difficult due to some countries’ attempts to “evade” doing the work required and the talks themselves.

“A whole range of our partners are still trying to evade concrete work, the talks, and to limit the issue to abstract calls on the necessity of President Assad’s departure,” Mr Lavrov said, calling it an approach that distracts from work that brings results.