Istanbul (CNN) -- Turkey is reacting angrily Tuesday to the French Senate's approval of a law criminalizing the denial of genocide, including that of the Armenians at the end of the Ottoman Empire.
"Guillotine to History" and "Guillotine to Thought," blared the front pages of two Turkish newspapers. "He massacred democracy," announced another newspaper, Hurriyet, next to a front-page photo of French President Nicolas Sarkozy.
In the run-up to Monday's late-night vote in the French Senate, the Turkish government made no secret it was vehemently opposed to the French law, warning it could cause permanent harm to Franco-Turkish relations.
The Turkish foreign ministry put out a pre-dawn statement condemning the law Tuesday. Later, however, Turkey's hot-tempered prime minister surprised some observers, when he called for a "period of patience" in a televised speech.
"A mistake was made... history cannot be judged or written by parliaments," said Recep Tayyip Erdogan, in remarks before lawmakers from his ruling political party.
Denouncing the French law as racist and a "massacre of freedom of thought," Erdogan added, "We have not lost our hope yet that this mistake can be corrected."
The Turkish leader said his government would lobby for a petition of 60 French lawmaker signatures to block the law in France's Constitutional Council.
According to the French legislation, "those who have publicly denied or trivialized crimes of genocide," can face a year in prison and/or a 45,000-euro fine.
The law does not specifically mention the World War I massacre of hundreds of thousands of ethnic Armenians by Ottoman Turks. But most of the seven-hour debate in the French Senate Monday focused on the memory of the Armenian genocide.
Within minutes of the 127-86 vote in favor of the law in Paris, Armenia's foreign minister issued a statement of gratitude that declared France "a genuine defender of universal human values."
"This day will be written in gold," wrote Edward Nalbandian.
Every year, Armenians around the world commemorate the 1915 slaughter of more than 1.2 million ethnic Armenians.
The Turkish government rejects the term "genocide" to refer to this dark and bloody chapter of history. Many Turkish politicians and historians argue Muslim Turks were also massacred by Armenian militias in the final days of the Ottoman Empire.
Instead, Ankara expends significant political capital and issues threats in an attempt to block initiatives in the U.S. Congress to formally term the killings of Armenians as "genocide." The United Nations defines genocide as the killing of, injuring of, or displacing of members of a national, ethnic, racial or religious group with the intent to destroy the group.
After the French lower house of parliament passed the genocide law in December, Turkey temporarily withdrew its ambassador from Paris and suspended military ties with France.
Turkish politicians have warned of further sanctions against France if Sarkozy allows the new law to go into effect.
But in an interview with CNN Monday, the head of the Turkish parliament's foreign affairs committee deliberately avoided saying what those measures might be.
"There's always ambiguity in politics and diplomacy," said Volkan Bozkir. "There will be some (measures)... which will hurt France more than Turkey," he warned.
Turkey and France enjoyed more than $14 billion in bilateral trade last year. They are also partners in the NATO military alliance.
CNN's Saskya Vandoorne contributed to this report from Paris