A memorial service has been held in St Petersburg for the 224 victims of the Russian passenger plane that crashed in the Sinai desert last weekend.

Cathedral bells at St. Isaac's tolled 224 times in memory of each person killed.

Meanwhile, It's reported investigators looking into the crash are "90 percent sure" a noise heard on one of its black box recorders was an explosion caused by a bomb.

The Russian government says it's brought home 11,000 of its citizens from Egypt in the last 24 hours.

Reporter Alex Rossi is in Sharm el-Sheikh in Egypt;