A century after her forebears fled massacres in Turkey for Armenia, Alla has gone the other way, hoping to win Turkish citizenship after leaving her impoverished homeland.

She works as a nanny in Turkey but fears deportation, one of thousands of undocumented workers from the former Soviet republic who feel hostage to a decades-old diplomatic dispute.

The conflict dates back to the killings of up to 1.5 million Christian Armenians by Ottoman Muslims that were being commemorated on Sunday, with tensions between Armenia and its Turkey-backed neighbour, Azerbaijan, especially amplified this year.

"We live in fear they (the Turkish authorities) can kick us out if something happens," said Alla, who declined having her full name published because of her illegal status in Turkey.

"When I get home from work, I thank God 1,000 times nothing happened," she said. "If I get citizenship, I won't be afraid."

Estimates put the number of Armenians here between 10,000 and 30,000. A bus ticket bringing them from Yerevan to Istanbul and, they hope, a better life costs the equivalent of about $50.

Their numbers are dwarfed by the 3 million Syrians and hundreds of thousands of Iraqis who have fled war but Armenian migrants feel vulnerable to the changing political winds.

Armenia, along with most Western scholars and two dozen nations, says the 1915 massacre was genocide. Turkey accepts that Armenians were killed during the upheaval of World War One but rejects declarations that it was genocide.

Animosity between the neighbours, whose border is shut, have flared this month after clashes between Muslim Azerbaijan and Armenian-backed Christian separatists in Nagorno-Karabakh, a region inside Azerbaijan that is controlled by ethnic Armenians.

Turkish President Tayyip Erdogan said the deaths of Azeris "seared our souls" and blamed Armenia for the outbreak of the worst clashes since a 1994 ceasefire in Nagorno-Karabakh after a war that killed thousands of people on each side.

Turks took to social media to denounce Armenians as "murderers" and proclaim Nagorno-Karabakh "Turkish territory".

"We hear rumours they will kick out Armenians because of the Azerbaijan matter," said Alla, 54. "This hate will never end."

THREAT OF DEPORTATION

Angered by international efforts to deem the century-old killings genocide, Erdogan has threatened to "deport" Armenian migrants. But he has also moved towards reconciliation, expressing condolences over the loss of life in 2014 and sending a minister to church services marking the centennial last year.

Garo Paylan, who in 2015 became one of three lawmakers of Armenian descent to enter Turkey's parliament in 50 years, this week brandished photographs of Armenian deputies killed in 1915 and demanded the assembly investigate their deaths.

"The reason I persist on this 100-year-old issue is because it continues to haunt Turkey," Paylan told Reuters.

This year commemorations were to be more muted than in 2105, with a handful of memorials planned.

Turkey cut ties with Armenia in 1993 at the height of the war in Nagorno-Karabakh. It agreed to restore relations under protocols in 2009 brokered by the United States, Russia and France but the deal did not have Azerbaijan's blessing.

"A renewed conflict could potentially draw in Turkey. It is Russian soldiers guarding Armenia's border with Turkey," said Aybars Gorgulu of the Public Policy and Democracy Studies think tank. "Sooner or later Turkey wants to normalise with Armenia."

Enmity towards Armenia leaves Turkish citizens of Armenian descent exposed, said Yetvart Danzikyan, editor-in-chief of Agos newspaper, which serves 60,000 Armenians out of a population of 78 million. The community faces pressures such as property seizures, poorly funded schools and sporadic violence.

A teenage gunman killed Danzikyan's predecessor, Hrant Dink, in 2007. A court this week began trying senior security officers accused of complicity.

"The state always leaves open wounds," Danzikyan said.

Alla's family fled strife and starvation that gripped the province of Igdir during World War One and the subsequent War of Independence that forged the modern Turkish Republic in 1923. Her grandparents found refuge across the border in Armenia.

Alla now earns $700 a month to support her mother and two children. An adult daughter, who was disabled, died this year.

Low-skilled labourers, especially women, struggle in landlocked Armenia, where per-capita income is about $4,000 an unemployment hovers at 17 percent, according to the World Bank.

Changes to immigration law in 2014 encouraged some Armenians to seek residency, but they must show large savings and pay fines. Alla said her penalty would amount to four months' wages.

New arrivals help sustain a dwindling community that flourished in these lands for four millennia until 1915.

Armenian migrants fill the pews of a Protestant house of worship every Sunday to sing exuberant hymns. The basement serves as an informal primary school with 140 immigrants.

A volunteer said Turkish authorities turn a blind eye so the school can follow the Armenian educational system.

One in three Armenians here does not plan to return home, said Anna Muradyan, a Yerevan-based independent researcher.

"They're aging, their children in Turkey have adapted and know Turkish. If Turkey doesn't expel them, they want to stay," she said.