MOSCOW — The suicide bomber who killed 35 people in an attack on a Moscow airport last week was a 20-year-old man from the North Caucasus, investigators said Saturday.

The mangled body of the man had been identified, a spokesman for the national investigative committee told the news agency Interfax, though he did not give a name.

The case had been solved and further suspects were being sought, the spokesman said.

About 180 people were injured in Monday’s attack at Domodedovo airport, Moscow’s busiest, dozens of whom were still being treated in hospitals.

Immediately after the attack investigators had blamed militant Islamist groups from the North Caucasus — which includes the republics of Chechnya, Ingushetia, Dagestan, North Ossetia and Kabardino-Balkaria — in particular singling out the Nogay Jamaat terrorist group.

Numerous radical Islamist groups have been fighting for an independent “”emirate”” in the North Caucasus for years as the Kremlin has struggled to impose peace on the region, plagued by poverty and high unemployment.

According to a Saturday report by the business daily Kommersant, the explosive belt worn by the bomber had been remotely activated.

President Dmitry Medvedev on Saturday gave written instructions to premier Vladimir Putin, giving him until March to put forward proposals on an improved security system for public transport.

A law on the stricter regulation of explosives should also be put forward by July, Medvedev said.