Saudi Arabia has offered for the first time to send ground troops to Syria to fight Islamic State, its defence ministry said on Thursday.

“The kingdom is ready to participate in any ground operations that the coalition (against Isis) may agree to carry out in Syria,” said military spokesman Brigadier General Ahmed al-Asiri during an interview with al-Arabiya TV news.

Saudi sources told the Guardian that thousands of special forces could be deployed, probably in coordination with Turkey.

Both countries are committed to the removal of Syrian president, Bashar al-Assad, and have grave doubts about the prospects for a political settlement of the crisis without further military pressure on Damascus. Saudi Arabia and Turkey set up a military coordination body a few weeks ago.

Saudi Arabia was one of the first Arab countries to join the anti-Isis coalition in September 2014 and mounted several air strikes on targets in Syria. But these diminished rapidly last March when it launched its intervention in neighbouring Yemen. The use of ground troops has been hinted at in the past, but the latest announcement is formal and serious, the sources said.

Despite an increasingly strained relationship with the US – especially over the nuclear deal with Iran, the Saudis’ strategic rival – the kingdom is keen to do more to demonstrate its readiness to fight terrorism. Saudi Arabia has been repeatedly targeted by Isis in recent months, and is often accused of being an incubator for violent extremism.

Asiri suggested that recent progress against Houthi rebels in the war in Yemen was allowing Saudi Arabia to free up forces for deployment in Syria. A decision could be taken at a Nato summit in Brussels next week.

“There is frustration with the current efforts put in place to fight Daesh,” said the Saudi analyst Mohammed Alyahya.

“Increasingly, it seems that none of the forces on the ground in Syria (besides rebel groups) is willing to fight Isis. The Assad regime, Iran, Russia, and Hezbollah are preoccupied with fighting Bashar al-Assad’s opposition with one ostensible goal: to keep Bashar al-Assad in power, irrespective of the cost in innocent Syrian lives.”