MOSCOW (Reuters) – Two female suicide bombers killed at least 38 people on packed Moscow metro trains yesterday, stirring fears of a broader campaign in Russia’s heartland by Islamists from the North Caucasus.

Prime Minister Vladimir Putin, who cemented his power in 1999 by launching a war to crush Chechen separatism, broke off a trip to Siberia, declaring “terrorists will be destroyed”.

Witnesses described panic at two central Moscow stations after the blasts, with morning commuters falling over each other in dense smoke and dust as they tried to escape the worst attack on the Russian capital in six years.

At least 72 others were injured, many gravely, and officials said the death toll could rise. Russia’s top security official said the bombs were filled with bolts and iron rods.

No group immediately claimed responsibility, but Federal Security Service (FSB) chief Alexander Bortnikov said those responsible had links to the North Caucasus, a heavily Muslim region plagued by insurgency whose leaders have threatened to attack cities and energy pipelines elsewhere in Russia.

“A crime that is terrible in its consequences and heinous in its manner has been committed,” Putin told emergency officials in a video call.

“I am confident that law enforcement bodies will spare no effort to track down and punish the criminals. Terrorists will be destroyed.”

The Kremlin had declared victory in its battle with Chechen separatists who fought two wars with Moscow. But violence has intensified over the past year in the neighbouring republics of Dagestan and Ingushetia, where Islamist militancy overlaps with clan rivalries, criminal gangs and widespread poverty.

The chief of the FSB, the main successor to the Soviet-era KGB, said: “Body parts belonging to two female suicide bombers were found … and according to initial data, these persons are linked to the North Caucasus.”

Russian Foreign Minister Sergei Lavrov said militants on the Afghan-Pakistan border may have helped organise the attacks.

Some Russian officials have said North Caucasus insurgents have ties to al Qaeda whose leaders are thought to be in hiding along the Pakistan border, but many analysts dispute any link.

Asked if there could have been any foreign involvement in yesterday’s attacks, Lavrov did not mention any group by name, but Interfax quoted him as replying: “I do not exclude that.”

Yessterday’s metro attacks are likely to turn the North Caucasus into a major political issue. Critics said the attacks demonstrated the failure of Kremlin policy in Chechnya, where human rights groups accuse Russian forces of brutality.

“They are simply beasts,” Russian President Dmitry Medvedev said of the bombers after laying a bouquet of red roses on the platform of one of the metro stations.

“We will find and destroy them all,” he said.

The first blast tore through a metro train just before 8 a.m. as it stood at the Lubyanka station, close to the headquarters of the FSB. It killed at least 23 people.

A second blast, less than 40 minutes later in a train waiting at the Park Kultury metro station, opposite Gorky Park, killed 12 more people, emergencies ministry officials said. Another three people died in hospital.

Reuters photographers saw body bags being brought out of both stations. Some of the wounded were airlifted to hospitals in helicopters and central Moscow was brought to a standstill as police closed off major roads.

“Everyone was screaming,” said Valentin Popov, 19, a student who was on a train at the Park Kultury station. “There was a stampede at the doors. I saw one woman holding a child and pleading with people to let her through, but it was impossible.”

European Union leaders condemned the bombings and US President Barack Obama called the Kremlin to offer condolences.

“President Obama said that the United States was ready to cooperate with Russia to help bring to justice those who undertook this attack,” the White House said in a statement.

The Russian rouble fell sharply on the bombings, but later regained ground, with traders arguing the bombs were unlikely to undermine the strength of the currency.

“The Russian stock market is more than stable, the rouble is stable,” said Anatoly Darakov, head of Russian equity trading at Citi in Moscow. “It’s not the first blast in Moscow.”