Sirens wailed across Israel on Monday, bringing millions of people to a halt for two minutes as they remembered the six million Jews who were killed during the Nazi Holocaust.

The annual ritual, which takes place at 10:00 am (0700 GMT), is a central part of Holocaust Memorial Day which began at sundown on Sunday.

All the country's radio and television stations also fell silent, interrupting a string of broadcasts and documentaries about the Nazi genocide and interviews with those who managed to survive it.

As the sirens rang out, buses, cars and trams ground to a halt across the country, people standing silently next to their vehicles in a show of respect.

This year, the ceremonies are largely dedicated to the memory of the fighters of the Warsaw ghetto on the 70th anniversary of the uprising when hundreds of poorly-armed paramilitaries rose up in Europe's first urban revolt against Nazi Germany.

During the morning, top Israeli dignitaries including Israeli Prime Minister Benjamin Netanyahu and President Shimon Peres laid wreaths during a ceremony at the Warsaw ghetto monument at Yad Vashem Holocaust museum which was also attended by US Secretary of State John Kerry and Canadian Foreign Minister John Baird.

Events marking the anniversary began at sundown on Sunday with another ceremony at Yad Vashem at which Netanyahu -- referring to the threat from Iran's nuclear programme -- said Israel would never put its fate into the hands of other countries, even friends.

"What has changed since the Shoah (Holocaust) is our determination and our capacity to defend ourselves with our own means," he said.

Memorial events were to continue throughout the day at various locations across the country, including a special session of parliament which will be devoted to the memory of the dead.