The zones -- worked out in a meeting between U.S. envoy Elizabeth Jones and Turkish Foreign Ministry Deputy Undersecretary Halit Cevik in an undisclosed Ankara location -- would provide a safe haven inside Syria to establish humanitarian corridors to besieged population centers, Istanbul's Hurriyet Daily News reported.
Washington has in the past turned down Turkish appeals to help set up safe zones.
Prominent members of Congress, including Sen. John McCain, R-Ariz., called last month for increasing intelligence and helping create safe zones in rebel-held areas.
The plans discussed Thursday would not necessarily be implemented any time soon, the News said.
Such safe zones could also be used by rebel forces, diplomats say.
U.S. and Turkish officials had no immediate comment on the Turkish newspaper's report.
The Thursday meeting took place as French Defense Minister Jean-Yves Le Drian urged the international community to consider backing a no-fly zone over parts of Syria.
The U.S.-Turkish plans under discussion included a strategy to address the possibility the Assad regime would use its chemical and biological weapons in an attack, the newspaper said.
U.S. Secretary of State Hillary Clinton said in Turkey this month, "In the horrible event that chemical weapons were used, we discussed what that would mean in terms of response and of humanitarian and medical emergency assistance and what would need to be done to secure those stocks and prevent them being used or falling into the wrong hands."
U.S. President Barack Obama threatened military action against Syria Monday if evidence suggested President Bashar Assad's regime was moving chemical or biological weapons.
"We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized," Obama told reporters at the White House.
"That would change my calculus. That would change my equation."
The "operational meeting" in Ankara, which the British newspaper The Guardian also reported on, came as British Prime Minister David Cameron said he supported Obama's military threat.
The Pentagon has made contingency plans to send small teams of special operations troops into Syria to protect or destroy chemical weapons stockpiles if they are left unguarded or the White House concludes they're in danger of falling into unwanted hands, including extremist groups linked to al-Qaida or Hezbollah, the Los Angeles Times reported.
Russian Deputy Foreign Minister Gennady Gatilov said Russia had "guarantees" from Syria that its chemical-weapons arsenal would not be moved or used.
Diplomats told The Guardian the Turkish meeting was also intended to reassure Ankara Washington would help prevent the conflict from spilling across the border and destabilizing its NATO ally.
Fighting in Syria intensified in Damascus Friday as regime forces stepped up efforts to win back control of parts of the capital and surrounding areas, residents and rebel forces said.
The intensification followed an offensive with heavy shelling by Syrian troops Thursday in the Damascus suburb of Darayya, residents said and videos posted on YouTube indicated.
The opposition Local Coordination Committees of Syria said 53 people were killed in Darayya Thursday.
"The situation in the city is grave due to the number of wounded and the inability to rescue or treat them," it said on its Web site.
The violence around the capital Thursday coincided with the departure from the country of U.N. monitors, whose mandate expired and was not renewed due to Syria's deteriorating conditions.
The Syrian Observatory for Human Rights said more than 100 people were killed across the country, including more than 20 regime troops.
Fighting raged in the northern city of Aleppo, where the rights group Amnesty International said artillery, mortar fire and airstrikes by Assad forces has killed mostly civilians, including children.
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