Egyptian President Abdel Fattah el-Sisi and British Prime Minister David Cameron last week (Photo:Getty Images)

A week after the crash of a Russian airliner carrying 224 passengers in the Sinai desert its official cause is yet to be established. Evidence is increasingly pointing to foul play or terrorism. The UK foreign secretary, Phillip Hammond, said there is a 'significant possibility' the plane was brought down by an onboard explosion, most likely by a bomb smuggled into the cargo hold, a scenario supported by US officials.

Russian and Egyptian experts in charge of the official investigation, as well as officials from both countries, remained cautious for most of the week. Yet on Friday, Russia suspended flights to all Egyptian airports over terrorism fears. Meanwhile, the Egyptian head of the international team investigating the crash, Ayman al-Muqaddam, maintained it is too early to say what caused it.

As one observer in the Guardian rightly commented, such caution is somewhat self-serving. An attack would derail claims that order and security has been restored to Egypt since the ousting of former President Morsi, threaten what remains of Egypt’s post-Arab Spring tourism industry, and detract from Russia’s domestically popular intervention in Syria.

Nonetheless, a more definite verdict on the crash, particularly in the absence of publicly disclosed evidence, will surely take time. What is clear is that the crash will have repercussions for the war on terror — globally, regionally, and locally — and impact counter terrorism co-operation between Western countries and their allies in the region.

It could signal a shift in the strategic aims of the local jihadist insurgency in the Sinai Peninsula. A variety of militant groups, some of them with links to ISIS such as Ansar Beit el-Maqdis (ABM), had been targeting army, police, and state institutions, but the tourist industry in Sinai had mostly been left alone.

As other analysts have argued, if ISIS is responsible for the downing of this plane it would mean a significant escalation of its operational capabilities. Until now, it has relied on high-profile lone wolf attacks. If ISIS has managed to turned one of its affiliates into an operational arm that has targeted Russia over its involvement in Syria, the increased regionalisation of a local conflict has entered a new and dangerous phase.

Many Western countries, including the UK, have responded to this perceived new threat by suspending flights to and from Sharm el-Sheikh, and advising against all but essential travel to the airport. The move by the UK government infuriated the Egyptian foreign minister, and could not have come at a more awkward timing with Egyptian President Abdel Fatah el-Sisi in London for a visit with UK Prime Minister David Cameron.

The visit was intended to reset UK-Egyptian relations post-Morsi and discuss the fight against terrorism and extremism in the region. While it is unlikely that both countries will let the crash get in the way of business, it highlights the tensions between the West and Egypt in the war on terror in the Sinai Peninsula.

Already, Egypt’s counter-terrorism strategy has left many Western governments — who often have competing views on how best to secure Egypt’s stability — in a quandary. Seeking to balance security and reform interests in the region, they have been unable to persuade regional allies such as Egypt to adopt a different counter-terrorism strategy.

Rather than addressing the flaws in Egypt's counter-terrorism strategy exposed by the crash, it is likely that President Sisi will strike back at the militants with even more brute force and use the attack to reinforce his authoritarian hold over the country. This would make a bad situation even worse.