An asylum seeker arrested in an Italian counter-terror operation is alleged to have travelled around London and the rest of the UK scouting potential targets.

Hakim Nasiri, from Afghanistan, posted pictures of himself outside Buckingham Palace and the Shard, and was also pictured on a train travelling through south-east London.

The 23-year-old was arrested with two other men this week after pictures of potential targets in London, Paris and Rome were found on mobiles.

Targets in London are said to have included the Westfield Shopping Centre in Stratford, West India Quay, the Sunborn Yacht Hotel in Royal Victoria Dock the South Quay footbridge to Canary Wharf, and an Ibis Hotel on Victoria Dock Road.

An airport, port and shopping mall are feared to have been on a possible hit list drawn up by a group "making preparations", according to Italian prosecutors.

Vincenzo Molinese, a military police colonel in the town of Bari where Nasiri was arresred, told the Daily Mail that images found on Nasiri's phone of him apparently holding a machine gun "were probably taken in the back room of a supermarket in England".

Nasiri was arrested at a home for asylum seekers in Bari on Wednesday. He is understood to have been held on suspicion of subversive association with the goal of international terrorism.

Two other men, Afghan Gulistan Ahmadzai, 29, and Pakistani Zulfiqar Amjad, 24, who were arrested in Milan on suspicion of aiding illegal immigration, had obtained international protection status in Italy.

Two more suspects are thought to have returned to Afghanistan.

At a news conference on Tuesday, prosecutor Roberto Rossi said there was no evidence an attack was imminent, but added: "It is clear they were making preparations."

Analysis of phones seized from five men found filming in a shopping centre in Bari in December uncovered photos of sites in London, Paris and Rome, as well as images showing "ideological hatred of the West and support for terrorism in Afghanistan", prosecutors said.

They reportedly included images of disfigured US soldiers and dead British troops being repatriated.

