Plotters of the twin suicide blast at Moscow subway stations that killed 38 people could have links with the terror network based in the Afghanistan-Pakistan border region, Russia said on Tuesday.
The deadly blasts in the subway could have been organised with support from abroad, Russian Foreign Minister Sergei Lavrov said.
"I do not rule this out, nothing can be ruled out here," he said.
The minister said that Moscow "is well informed about the so-called no-man's land on the border between Pakistan and Afghanistan," where "the terrorist underground has entrenched itself".
"We know that many terrorist attacks - not only in Afghanistan, but in other countries too - are plotted in that area... Sometimes, the trail leads to the Caucasus," he said and urged the global community to coordinate efforts in the fight against international terrorism and its financial sponsors.
Two female suicide bombers attacked the Lubyanka and Park Kultury stations of the Sokolnicheskaya subway line during the morning rush hour Monday. The first blast occurred at 8:00 am (0930 IST) and the second about 40 minutes later. At least 38 people were killed and more than 70 injured.