A Belgian man claiming to fight for Isis in Iraq has ridiculed the country’s security forces for letting him slip out the country “like a knife cutting through soft butter”.

The jibes on Twitter emerged as two suspected jihadists were shot dead in the town of Verviers as special forces foiled an “imminent” attack on police and another 30 people were arrested on suspicion of terror across Europe.

The man, calling himself Abu Mariya Belgiki – not his real name – taunted authorities last week while documenting his new life supposedly living under the “Islamic State”.

“Don't want to hurt anyone's feelings, but Belgian intelligence agency is the laziest and the dumbest in the world probably...they kept me under surveillance since I was 14. And I passed through Brussels airport like a knife cutting through soft butter,” he wrote on 9 January from the account, which has since been suspended.

Abu Mariya Belgiki claims to have left Belgium to fight with Isis in Iraq

As the mounting terror unfolded in France after the massacre at Charlie Hebdo’s offices, Belgiki praised the gunmen.

He said he was told the news by his “ameer” (leader) as he got ready for bed.

“Was going to bed yesterday, my ameer yells and says ‘France you know France?’ I said yes it’s south of Belgium. He said ‘yes I know’,” he wrote.

“He said ‘ikhwa [brothers] did operation there and killed 12’. I was like whooaaaaaaa what are the ikhwa in belgium waiting for......:)”

Belgiki said he had gone from a life in Belgium "under oppression" to living under the "flag of unity" in Iraq, describing fighting rival group Jabhat al-Nusra and claiming to be armed with M16 rifles stamped “US property”.

In pictures: Counter-terrorism raid in Belgium Show all 10 1 /10 In pictures: Counter-terrorism raid in Belgium In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Police block the street of Colline in Vervier Eastern Belgium, 15 January 2014, after an anti terrorist operation EPA In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Police block a street in Vervier, eastern Belgium, following an anti terror operation. EPA/OLIVIER HOSLET In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Police forensic experts inspect the scene in Rue de la Colline in Verviers, Belgium EPA In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Belgian police inspect the entrance of an apartment in central Verviers, a town between Liege and the German border Reuters In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Riot police secure the scene in Rue de la Colline in Verviers, Belgium EPA In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Police investigate a shootout in a street in Verviers, Belgium AP In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Eric Van Der Sypt, center, from the Brussels federal prosecutors office speaks with the media at police headquarters in Brussels AP In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Belgian police exit a building in Palais street, near Colline street in Verviers, eastern Belgium AFP In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Police block the street of Colline in Vervier Eastern Belgium EPA In pictures: Counter-terrorism raid in Belgium Counter-terrorism raid in Belgium Marc Elsen, Mayor of Verviers and President of Local Police gives a press briefing in Rue de la Colline in Verviers, Belgium EPA

He wrote in Flemish that he had met a 16-year-old Dutch boy who was fighting for Isis after leaving home, according to the MEMRI Jihad and Terrorism Threat Monitor.

The website, which originally spotted the tweets, said a message from 5 January talked of his daily routine “making Wudu [prayer], jets …hanging clothes in the sun, jets… playing with cats in the garden, jets”.

Belgiki’s last messages before his account was taken down contained threats to Egypt, Libya, Yemen and Algeria vowing that the “khilafa (caliphate) is spreading as are the flames of war”.

His last post read: “To France with much hate: the fighting has just begun.”

Abu Mariya Belgiki retweeted a message saying 'Je suis Kouachi' in admiration of the brothers who carried out the Charlie Hebdo massacre (Twitter)

A spokesperson for Belgium’s federal magistrate confirmed to The Independent that an investigation into the claims had been started but would not comment further.

It was unclear whether Belgiki knew of the two suspected terrorists shot dead in Belgium on Thursday, who were believed to be friends who had fought for Isis in Syria.

Searches suggested they had been planning to dress as police to launch a deadly gun and bomb attack on police officers in the street or inside stations.

Special forces who raided a property in the town of Verviers, killing the two men as snipers patrolled the rooftops, found Kalashnikovs, handguns, ammunition, falsified documents, cash and bomb-making equipment among police uniforms.

A picture, believed to show Redwane Hajaoui and a friend, posted on his Facebook from Aleppo, Syria (Facebook)

The same type of gun was used by the Kouachi brothers in the massacre at the offices of Charlie Hebdo in Paris.

Eric Van der Sypt, a federal magistrate, said that Belgian authorities had averted a “second potential Paris” by stopping the attack, which would have taken place “in a matter of hours”.

The dead suspects' identities have not been officially confirmed but Belgian newspaper Sudpresse reported that the families of Redwane Hajaoui, also known as Abu Khalid al-Maghribi, and Tarik Jadaoun, also known as Abu Hamza Belgiki, were concerned.

A total of 13 suspects are being held in Belgium and two more who were targeted in the same investigation have been detained in France.