Italy Highway robbery Lodi
Burning vehicles are seen at the scene of a highway robbery in ItalyTwitter/Autostrade per l'Italia

Armed robbers blocked off a stretch of Italy's main freeway to launch a spectacular assault on an armoured security van - but came out empty-handed.

In scenes out of a thriller movie, shots were fired and several vehicles burnt during the botched heist near the northern city of Milan.

Early in the morning, gangsters threw nails and set three trucks and a car on fire to seal off a stretch of the A1 freeway and trap a security van and its two-vehicle escort.

The attackers, up to 15 men according to early reports, subsequently opened fire on the convoy but the armoured car transporting valuables managed to flee.

Upon witnessing the escape of their targeted booty, the robbers sped away in get-away vehicles, which they later dumped nearby. A woman told police she was carjacked by armed men in the same area.

The incident caused a massive jam on the highly-trafficked artery connecting Milan to Naples.

The security van belonged to security firm Gruppo Battistolli, which suffered from a similar but successful attack last year.

In that incident, 10 Kalashnikov-wielding gangsters reportedly escaped with about €10m (£8.5m) in gold and cash after attacking another van travelling on a freeway near Como.