Well it's not true that the Ukraine/russian border is secure, it keeps getting infiltrated by 3 so called rebel russian groups, who keep taking villages and holding them, was it three times in the last week ? Not so impenetrable perhaps.
On the "why didn't they martyr" themselves question, maybe because they had other attacks planned ? IS haven't always martyred themselves, they didn't in Paris, they tried to and did escape, to be arrested at a later date. Similar in London and Brussels, they don't solely rely on suicide bombings.
Do I trust the russian authorities to tell the truth, of course not, they lie about almost everything, but why would foreign intelligence know/warn of this a week ago ?
It was also said that an IS attack on a synagogue in moscow had been foiled in the last few weeks.
Who knows what exactly has gone on here, as usual with russia we'll probably never know.
That supposed rebel Russian group border activity is disputed—it could be real, it could be more fabrication to justify certain “response” operations. Even so, Russia has been strengthening boarder security largely because of those claimed operations.
Regarding IS attacks elsewhere over the last decade or so, nearly all of the terrorists in the 2015 Paris attacks either killed themselves or were killed by police on the day, and the two that fled were killed in a shootout with French police during a raid five days later.
All of the 2017 London terrorists were killed by police on the day.
The 2016 Brussels attack was a coordinated series of suicide bombings (or attempted bombings), and the only reason two of the terrorists fled was because they decided they didn’t want to kill themselves.
The vast majority of recent IS claimed terrorist attacks have been suicide bombings, with a number of gun attacks resulting in martyrdom, as well as few vehicle-related killings (in which nearly all of the perpetrators were killed or killed themselves at the scene).
Unless IS is shifting their terrorist activities to much higher risk operations that allow for perpetrators to be taken alive and interrogated for information, this attack is well outside their normal approach.
As to why foreign intelligence would warn about a possible attack like this in Russia, including Ukraine: most alerts directed toward Russia these days aren’t intended as genuine warnings of impending harm, or even primarily meant for Russian audiences at all. They are notices of awareness of potential Russian operations (i.e. “we know what you’re planning”) and preemptive declarations of “we weren’t involved” (whether that is true or not). Quite a few of them are meant to combat Putin dis/misinformation campaigns.
I completely agree that Russia (specifically Putin) lie about almost everything and so cannot be trusted. As is the case with our and American intelligence, to be fair.
And that we may never fully know what actually happened yesterday. (or if it was a legitimate lapse in Russian intelligence and counter-terrorism or if it was a false flag operation, either direct or indirect).
