Russia has boasted it is practising shooting down missiles as the country's parliamentary hardliners demanded a military response to any US air strike on Syria.

The Russian defence ministry said that naval jets from its Pacific fleet had conducted exercises to “intercept and destroy a low-flying long-range cruise missile”.

Two former Russian officers turned politicians called on the Kremlin to use military force should Donald Trump approve an attack on the Syrian regime.

Meanwhile Mr Trump, the US president, was under growing pressure from his own senators to follow through on tough rhetoric over the Syrian chemical attack.

Lindsey Graham, the Republican senator from South Carolina, said that failing to approve a military response would be “the biggest mistake of his presidency”.

Leading Western countries are debating how to punish Bashar al-Assad, the Syrian president, for a suspected chemical attack that killed at least 60 Syrians, including children, on Saturday.

Defence expert: Russia can hit US missiles in Syria - but it may run out of interceptors