London, Sept 16: In a major breakthrough for the investigators, the Kent Police on Saturday arrested an 18-year-old man from the port area of Dover, in connection with the terror attack in London’s tube train. He was detained under section 41 of the Terrorism Act.

Neil Basu, the senior national coordinator for counter-terrorism policing, said the arrest made is a “significant development” in the case. He, however, added that the investigation is far from over. The threat level in UK, for the time-being, will remain at ‘critical’, the top security official told reporters.

The arrested 18-year-old would be transferred to a south London police station.

The progress in the terror investigation comes a day after UK Prime Minister Theresa May ordered troops in the nation to increase patrol in the civilian areas, as the country remains gripped under the fear of “Islamist violence”.

The terror strike on Friday – fourth major attack in UK this year – was carried out in the London underground metro while it was ferrying from the Parson Greens station. A total of 29 passengers were injured in the IED blast, which was reportedly planted by the perpetrator in a bucket, covered with freezer plastic. According to investigators, the attack could had been fatal if the IED would had completely detonated.

Hours after the carnage, extremist outfit Islamic State (ISIS) claimed responsibility for the assault. ISIS’ propaganda magazine Amaq said the blast targeting London’s public transportation service was carried out by its affiliated unit in the United Kingdom.

Using the pretext of terror attack in London, US President Donald Trump advocated a “tougher travel ban” in the States, even though, he added, “it is politically incorrect”.

Trump also went on to claim that the “loser terrorist” who carried out the attack was under the radar of Scotland Yard, adding that the law enforcement agencies should remain “pro-active”. The remarks of Trump were rebuked by PM May, who said it is “not helpful to speculate in such cases”.