Russia's shadowy military intelligence has found itself thrust into an unwelcome spotlight over glaring errors that exposed its agents' alleged role in the poisoning of Russian double agent Sergei Skripal and an attempt to hack into the global chemical weapons watchdog.

- Salisbury slips -

Britain identified the suspects in the poisoning of former Russian double-agent Sergei Skripal and his daughter in Salisbury in March after they visited the city twice in two successive days, their faces caught by numerous security cameras including close to Skripal's house.

After President Vladimir Putin called for them to appear on television, the two men appeared on Kremlin-funded RT channel, confirming their names were as on the passports used by the suspects: Ruslan Boshirov and Alexander Petrov.

Appearing awkward and possibly fearful, they made an unconvincing case that they were simply tourists keen to see Salisbury's 123-meter cathedral spire.

Russia's Fontanka newspaper and British-based investigative group Bellingcat revealed the men had traveled on passports with almost consecutive numbers, suggesting they were issued simultaneously, unlikely if they were simply businessmen holidaying together.

This also made it easier to spot other agents with similar passport numbers.

An official database accessed by Bellingcat showed the men's files had several signs they were not ordinary citizens, with Petrov's marked with a defense ministry telephone number.

Bellingcat revealed the man named as Ruslan Boshirov closely resembled Anatoly Chepiga, a highly-decorated officer with military intelligence agency GRU.

Even Kremlin-loyal tabloid Komsomolskaya Pravda confirmed the likeness with the help of a facial identification expert.

Investigative sites and media found photos showing Chepiga's picture on a wall of honor at his college and online mentions on his supposedly secret Hero of Russia medal.

Russia has officially denied that Boshirov is Chepiga and that anyone with that name won the country's top medal.

- Caught next to OPCW -

The Netherlands on Thursday said that in April it had caught Russian agents travelling on diplomatic passports as they attempted to hack into the world's chemical weapons watchdog OPCW in The Hague from their nearby parked car.

Two of their passports also had close-together numbers and one had a taxi receipt for a journey to a Moscow airport from a street where a GRU barracks is located, which the taxi company confirmed to Russian media is authentic.

Bellingcat checked passport details against a traffic police database available on the black market and found one had registered a vehicle at the address of the GRU barracks. In fact, a total of 305 people did so.

Such a step, making it easy to identify agents, is a sign of "notorious incompetence" and "banal corruption," wrote Alexander Gabuyev of the Carnegie Moscow Center on Twitter, suggesting officers would do this to get out of paying traffic fines.

Images of the agents turned out to be posted online on public resources including the website of an amateur football league and a dating site.

A Moscow municipal deputy, Anastasiya Bryukhanova, wrote on Twitter that she had spent an hour wandering round a GRU facility while campaigning, having simply "opened the gate and walked in" before being stopped.

The Kremlin or Russian military have not yet commented on the latest cyber attack allegations, while foreign ministry spokeswoman Maria Zakharova dismissed them as Western "spy mania".

- 'Too relaxed'? -

Until recently, Russians heard only about heroic triumphs of its military intelligence amid a patriotic drive by the Kremlin, Alexander Golts, a Russian military analyst told AFP, suggesting agents "got a bit too relaxed."

"Such sloppy work is the reality," he said, suggesting that western intelligence had known about Russian covert activities, but didn't make the information public until recently.

"Now every day brings us new disclosures which show the very great capabilities (of Western secret services) to gather and analyse information."

In fact, GRU made some serious errors in the past, Golts said, citing the Soviet-era case of Dmitry Polyakov, a general who trained its agents before being exposed as a double-agent for the US and shot in 1988.

"There are blunders everywhere where there is the human factor -- and Western intelligence also makes quite a few," he said.