It took Moscow a good 18 hours to respond to the UK's announcement that a bomb may have caused the downing of the Russian flight that crashed not far from the Egyptian resort town of Sharm el-Sheik. Granted Wednesday was a public holiday in Russia but it wasn't until mid-Thursday that the Kremlin's spokesperson, Dmitri Peskov, labeled the British statement as "unhelpful."

"Theories about what happened and the causes of the incident can only be pronounced by the [official] investigation," Peskov said.

He added, in a broad swipe at the UK, that he hoped those who had the new information would share their intelligence with the crash investigators. The UK has since said it believes a bomb may have been loaded into the hold of the plane and US President Obama has agreed a bomb is a "strong possibility." A number of European countries have revised their travel advisories for the area and some airlines have suspended flights to the resort town. Russia has now followed suit with Russian intelligence chief Alexander Bortnikov claiming it was a "reasonable" course of action until "we determine the real reason" for the crash.

One Russian deputy was quoted in the Russian press as saying he thought the UK's decision to stop flights to Sharm el-Sheikh was a 'geopolitical' decision aimed at undermining Russia's operations in Syria.

Russian reactions

Now there may be a number of reasons for Russia's initial resounding silence. Firstly the bomb theory comes from UK intelligence and while its saying it's a strong possibility, it's not a certainty. Secondly, the official investigation into the cause of the crash is still ongoing, and thirdly, there are some potentially significant political issues that need careful consideration before racing to make a comment - including how Russians will react to the news that they've been targeted by terrorists for their country's involvement in Syria, and how the relations between Russia and Egypt should be handled.

Muted reactions so far but for how long?

At the moment Russia wants to keep Egypt onside as a player in the fight against the "Islamic State" (IS) group in Syria. It's building bridges in the region in an attempt to forge a coalition against the terrorist group and accusing its ally of running a less than tight ship may not be to Russia's advantage. It's a relationship that will need to be handled with kid-gloves.

At home there is likely to be mixed reaction if a bomb attack is confirmed. Many Russians will question the involvement in an offensive against IS in a foreign country, saying the price they're having to pay is too high. At the same time however, the attack plays right into the Kremlin's hands. It has said its involvement in Syria is not just about defeating IS abroad but also about domestic security. Russia has 20 million Muslims within its borders. Its southern neighbors and former Soviet republics are predominantly Muslim with borders on Syria, Afghanistan and Iran.

There are estimates that up to 4,500 Russians are already fighting with IS in Syria and the video of a blonde, fair-skinned Russian-speaking terrorist wielding a knife and praising the crash as the first of many to come in retaliation for Russia's involvement in Syria is more than likely to raise the hackles of the bear rather than make it run in fear. As we've seen repeatedly, the Kremlin doesn't like to back down.

Game changer

If it is an IS-backed bombing it represents a departure from its usual game plan, according to MI6's former director of counter-terrorism intelligence, Sir Richard Barrett. Speaking on the BBC's Newsnight programme he said up until now IS had been about "state-building" but this was the most significant attack on an airliner since 9/11 and shows it is evolving from a regional player to one with a global reach.

But it's not just the West that may have to rethink its strategy in the region and over the past few days Russia has been slightly changing its tune and now says it doesn't care if Syrian leader Bashar al-Assad stays or goes; it's not a game-changer for the Kremlin. What is important, it claims, is ensuring there is no leadership void that could lead to the collapse of the country.

Russia's helping hand may be withdrawn

Domestically what will be playing on Russia's mind is how attractive this tragedy might be to the disaffected within its own borders.

Katherine Brown, an expert in terrorism from Kings College London who was also speaking on Newsnight, said IS was sending a strong message to Muslims in Russia that "they are not forgotten in the fight."

This will be a big concern for the Russian leadership and it's more than likely they won't take the downing of the plane or this type of threat lightly. Russia's reaction to Chechen extremist's bombings in Moscow was to virtually raze the region to the ground.

So perhaps Moscow's relatively quiet response is what they call 'mertvi shtil' - the calm before the storm.