Twenty-six countries have expelled Russian envoys in the past two days. NATO is also expelling seven diplomats in response to the attack. Pic/AFP

Moscow yesterday charged Washington had put "colossal pressure" on allies to expel scores of Russian diplomats, and vowed to retaliate. "This is the result of colossal pressure, colossal blackmail which is the main instrument of Washington on the international arena," Russian Foreign Minister Sergei Lavrov said.