Britain is to send 75 military personnel to help train moderate Syrian forces fighting on two fronts, against Islamic State and President Bashar al-Assad.

The training in small arms, infantry tactics and basic medical skills will take place in Turkey and is part of a US-led effort aimed at helping thousands of Syrian fighters over the next three years. The Syrian fighters are being screened to weed out those considered to be Islamist extremists.

The Commons voted in 2013 against direct British intervention in Syria, and the Ministry of Defence (MoD) does not regard the deployment as contravening this. Until now, the UK has only been involved in fighting against Isis in Iraq.

The move comes after stinging criticism in a recent Commons defence committee report about the limitations to British involvement in the fight against Isis, which is also known as Islamic State of Iraq and Levant (Isil). The MPs on the committee said the UK had mounted only a small percentage of the air strikes, had only a handful of troops based in Baghdad and had no clear strategy.

Michael Fallon, the defence secretary, announcing the new training deployment, said: “Britain remains at the forefront of coalition military efforts to support the Iraqi government in their fight against Isil. This effective and closely co-ordinated activity in conjunction with Iraqi and Kurdish ground forces has largely stalled the terrorists’ advances.

“But Isil must be defeated in both Iraq and Syria. In Syria, coalition airstrikes have supported the liberation of Kobane and have disrupted Isil’s logistics and supply lines. However, defeating Isil ultimately lies with local forces and we are helping to create effective ground forces in Syria, as well as in Iraq, so they can take the fight to Isil.”

Reuters reported that Syria’s Assad-backed state news agency, Sana, dismissed British support for the Syrian opposition as amounting to a “commitment to supporting terrorism”.

Fallon also announced that the UK would be sending two Sentinel aircraft to the region to improve surveillance of Isis in Iraq and track the laying of roadside bombs.

British planes were involved on Wednesday night in supporting Iraqi ground forces fighting against Isis in western Tikrit, the city north of Baghdad held by the Islamist militants.

The 75 trainers represent a relatively small contribution, reflecting Britain’s shrinking military force.

It follows another symbolic gesture last month when Fallon ordered the deployment of 75 trainers to Ukraine to help government forces in the fight against pro-Russian rebels.

On Wednesday, the MoD issued an unusually robust response to the Commons committee criticism, claiming to be at the forefront of the fight against Isis. It said the committee’s conclusions were based on out-of-date or inaccurate information, that there was a clear strategy, and that the number of air strikes and ground troops was higher than the MPs had suggested.