Israel is no longer a democracy but an "apartheid regime" devoted to cementing the supremacy of Jews over Palestinians, the country's best-known human rights group said in a report published Tuesday.

B'Tselem, which until now has confined its work to scrutiny of human rights issues in the Palestinian territories, has now also decided to look at what it calls Israel's "regime" between the River Jordan and the Mediterranean.

"More than 14 million people, roughly half of them Jews and the other half Palestinians, live between the Jordan River and the Mediterranean Sea under a single rule," B'Tselem said in a new analysis titled: "A regime of Jewish supremacy from the Jordan River to the Mediterranean Sea: This is apartheid."

The human rights group says that the traditional view of Israel as a democracy operating side-by-side with a temporary Israeli occupation in the territories "imposed on some five million Palestinian subjects ... has grown divorced from reality."

"Most importantly, the distinction obfuscates the fact that the entire area between the Mediterranean Sea and the Jordan River is organized under a single principle: advancing and cementing the supremacy of one group -- Jews -- over another -- Palestinians," B'Tselem said in its controversial analysis.

Years of injustice against Palestinians, culminating in laws that have entrenched discrimination, mean that "the bar for labeling the Israeli regime as apartheid has been met," B'Tselem said.

The allegation that Israel is an "apartheid state" has often been dismissed by rightwing Israelis and their support groups as anti-Semitic. But this argument will be harder to make now that Israel has been labelled this way by such a well-respected Israeli institution, albeit one that enjoys only minority support in its home country.

Israel's embassy in London dismissed the report as "not based on reality but on a distorted ideological view."