Patriarch Kirill of Moscow and All Russia led a memorial service for the Nevsky Express train blast victims on Sunday and called on the nation to unite in the face of terrorist threats.

Three cars of the high-speed train No. 166 bound from Moscow to Russia's second largest city St. Petersburg derailed Friday evening after an explosive device equivalent to 7 kg of TNT detonated on the railroad tracks, killing 25 people and leaving over 90 injured, with six still unaccounted for.

The attack occurred near the border between the Novgorod and Tver regions, some 400 kilometers (250 miles) northwest of Moscow. The train was carrying hundreds of passengers.

"Let our unity, our care about each other's peace and security leave no chance to those who want to sow fear, death and destruction," Patriarch Kirill, who heads the Russian Orthodox Church, said in a statement.

"We prayed today about those who died and we are praying about those who were injured... Our nation must not get used to such events," Kirill said after the memorial service he led in downtown Moscow's Christ the Savior Cathedral.

MOSCOW, November 29 (RIA Novosti)