It is not known what caused the blasts., which happened hundreds of kilometres from the Ukrainian border.

Paul Whelan, an American detained in Russia, was able to call home Friday after more than a week without contact with his family, his brother David said.

The Biden administration is blaming Russia for postponing meetings to discuss the nuclear arms agreement between the two countries that were scheduled to begin in Egypt on Tuesday, with a State Department spokesperson saying the decision was made "unilaterally" by Russia.