The alleged ethnic cleansing gave added weight to long-held suspicions Assad's seeking to establish a last-ditch stronghold in a region historically dominated by the minority Alawites if his regime's driven from Syria's capital, Damascus, where heavy fighting rages.
The alleged killings in the Tartous area were supposedly carried out by fighters of the National Defense Forces, a paramilitary organization made up largely of men recruited from minority groups who support Assad's regime.
The formation of the NDF underlines growing indications that the regime is under increasing pressure in Syria's 2-year-old civil war and that Assad is having to mobilize non-Alawites to replace growing military losses and desertions.
At least two massacres by pro-Assad forces were reported to have taken place Thursday and Friday in the Alawite heartland, with more than 100 people, including children, killed in the coastal towns of Baida and Banias.
Mass killings by both sides in the Syrian civil war have become increasingly common, but the reported killings in Baida and Banias suggest a possible systematic Alawite effort to drive out majority Sunnis from the region.
The Alawites, an esoteric offshoot of Shia Islam, total around 2.6 million, or 12 percent of Syria's 22 million population.
The Syrian Observatory for Human Rights, a pro-opposition monitoring group in Great Britain, said at least 50 Sunnis, including whole families, were killed in Baida.
It gave no death toll for Banias, but posted videos on the Internet showing bodies in the streets in pools of blood.
The observatory said the final death toll could be 100-200 but there's been no independent verification of the reported massacres.
"I estimate that hundreds of families have left and headed for nearby towns like Jableh and Tartous," said observatory Director Rami Abdulrahman.
As the war has progressed there's been growing speculation that there will be murderous reprisals against the Alawites for 40 years of brutal rule if the regime collapses.
This has spurred the idea of recreating the Alawite states that existed before the French took over Syria from the defeated Ottomans after World War I to establish a safe haven for Assad and his cohorts should Damascus fall.
This has since morphed into Assad's so-called Plan B.
The way things stand right, the plan seems to be to establish a redoubt for the regime and its followers in the Alawite heartland in northwestern Syria along the coast, no doubt redeploying most of the regime's weapons there.
This zone would include Syria's two main ports, Tartous and Latakia to the north, providing access to the outside world.
This enclave would adjoin northwestern Lebanon, where Assad's ally, Hezbollah, has its main stronghold along the border in the Bekaa Valley.
Hezbollah, Iran's main proxy in the Levant, would thus still be able to maintain an arms supply line from the Islamic Republic through Tartous and Latakia.
That would replace the current logistics corridor that's primarily an air link from Tehran to Damascus, with weapons then moved overland into the Bekaa, with a maritime channel.
This would suit Tehran very well, since although it would lose an allied regime it was steadily dominating, it would still have a strategic gateway to the Levant and the eastern Mediterranean.
In this manner, Hezbollah, with a vast arsenal that reportedly includes as many as 60,000 Iranian missiles supplied via Syria, would still be able to threaten Israel if it attacked Iran's nuclear infrastructure.
Even if Assad manages to establish this redoubt, there are no guarantees that the forces fighting him will allow him to maintain an Alawite bastion.
But, that apart, there are signs that when the regime is overthrown -- and that in the minds of many, inside and outside Syria, is a foregone conclusion -- the country could well fragment, a development the recreation of an Alawite entity in the northwest would encourage.
Any successor regime in Damascus is certain to be Sunni, probably dominated by Islamists. But if Assad's project materializes, it will control a greatly shrunken domain.