A Russian frigate capable of firing cruise missiles at targets up to 370 miles (600km) away has docked in the Syrian port of Latakia, ahead of what intelligence sources and rebels say is a new attack on Aleppo timed for when the world’s attention is focused on the American national election.

The Admiral Grigorovich joins the Admiral Kuznetsov aircraft carrier – Russia’s only one – and the Pyotr Velikiy (Peter the Great) nuclear-powered battle cruiser, both of which arrived at the Russian naval base in the regime stronghold of Latakia on the Mediterranean last week.

Russia’s Black Sea fleet, including the Kuznetsov, seven other war ships and three submarines, began its journey from Murmansk in the biggest Russian military deployment since the Cold War last month. While British officials dismissed the show of strength as “posturing”, the fleet poses a serious threat to rebels fighting the Russian-backed regime in Syria’s bloody civil war.

The Grigorovich uses formidable Kalibr land-attack cruise missiles, which have been deployed a handful of times since Russia began military intervention in Syria in September 2015.

The mass movement of ships and submarines to Syria’s coastline is part of what Nato intelligence expects to be an assault timed for when Washington DC is distracted by the general election on 8 November, although Russian Foreign Ministry official Andrei Kelin last week dismissed fears that the vessels will be used in a renewed attack on Aleppo as “absurd”.

Any such attack would come after the 18 October Russian-announced temporary moratorium on air strikes on rebel neighbourhoods, and amnesty for fighters and civilians wishing to leave the area, expired last Friday.

Dahiyet al-Assad - Aleppo Show all 16 1 /16 Dahiyet al-Assad - Aleppo Dahiyet al-Assad - Aleppo A girl who fled areas of conflict rides a vehicle in Dahiyet al-Assad, west Aleppo city, Syria REUTERS/Ammar Abdullah Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigade have a tea in a building under construction Getty Dahiyet al-Assad - Aleppo A rebel fighters' armoured vehicle in Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigades sit on a tank Getty Dahiyet al-Assad - Aleppo Abandoned magazine of shells after rebel fighters took control of Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Rebel fighters ride a pick-up truck with civilians who fled areas of conflict in Dahiyet al-Assad, west Aleppo city, Syria Reuters Dahiyet al-Assad - Aleppo A rebel fighter gestures with a girl who fled areas of conflict while they ride a pick-up truck in Dahiyet al-Assad Reuters Dahiyet al-Assad - Aleppo Smoke rises near a damaged road in Dahiyet al-Assad, west Aleppo city, Syria Reuters Dahiyet al-Assad - Aleppo Syrians carry their belongings as they leave the southwestern frontline neighbourhood of Dahiyet al-,Assad Getty Dahiyet al-Assad - Aleppo A view shows a damaged minaret of a mosque after rebel fighters took control of Dahiyet al-Assad, Syria Reuters Dahiyet al-Assad - Aleppo Rebel groups have pledged to push from newly captured positions in the Dahiyet al-Assad district towards Hamdaniyeh. Rebels and allied jihadists launched a major offensive on October 28, 2016 to break through government lines and reach the 250,000 people living in the city's east Getty Dahiyet al-Assad - Aleppo Rebel groups have pledged to push from newly captured positions in the Dahiyet al-Assad district towards Hamdaniyeh Getty Dahiyet al-Assad - Aleppo Rebel fighters from the Jaish al-Fatah (or Army of Conquest) brigades hold a position at an entrance to Aleppo, in the southwestern frontline neighbourhood of Dahiyet al-Assad Getty Dahiyet al-Assad - Aleppo Smoke billows from the frontline district of Dahiyet al-Assad following an attack by rebels on Syrian regime forces in the northern city of Aleppo Getty Dahiyet al-Assad - Aleppo Syrians carry their belongings as they leave the southwestern frontline neighbourhood of Dahiyet al-Assad Getty Dahiyet al-Assad - Aleppo People who fled areas of conflict ride a pick-up truck in Dahiyet al-Assad, west Aleppo city, Syria Reuters

East Aleppo has been subjected to heavy aerial bombardment and a renewed ground assault by President Bashar al-Assad’s troops and foreign militias since September which has killed more than 500 people.

The UN has said both sides may be guilty of war crimes in targeting civilian infrastructure during the fighting, some of the bloodiest in Syria’s almost-six-year-long civil war.

While the regime said that humanitarian corridors had been set up for civilians to leave the siege barricades, both sides accused the other of targeting checkpoints with mortar and sniper fire. Few people were reported to have left east Aleppo by Tuesday.

Aleppo offensive

The estimated 8,000 fighters left in rebel neighbourhoods – among them al-Qaeda-affiliated fighters – have been assisted since 29 October by a counter attack launched by allies on regime held parts of the city designed to break the siege.

Syrian government forces said on Tuesday they had managed to regain control of the strategically important 1070 Apartments district, which would put an end to the rebels’ momentum.

The UK-based Syrian Observatory for Human Rights confirmed the Syrian military’s claim, calling it the most significant gain by the government in Aleppo since September’s campaign was launched.