ISTANBUL — Turkey made it clear Thursday that it officially recognized a newly formed rebel coalition as the legitimate leader of the Syrian people, an important step in the group’s effort to attract legitimacy and, it hopes, more weapons to bring about the end of President Bashar Assad’s rule.
Turkey ‘‘once again reiterates its recognition of the Syrian national coalition as the legitimate representative of the Syrian people,’’ Turkey’s foreign minister, Ahmet Davutoglu, said in a speech at an Organization of Islamic Cooperation meeting in Djibouti, the tiny country on the Horn of Africa.
The announcement by Turkey, Syria’s northern neighbor and a haven for thousands of Syrian refugees and rebel fighters, was the third significant recognition of the new group this week.
On Monday, members of the Gulf Cooperation Council — Saudi Arabia, Bahrain, the United Arab Emirates, Oman, Qatar, and Kuwait — recognized the group, known as the National Coalition of Syrian Revolutionary and Opposition Forces.
On Tuesday, France became the first Western country to do so and said it was considering providing arms to the insurgent groups that have been engaged in a 20-month-long war with the government that has claimed nearly 40,000 lives.
Davutoglu’s comments Thursday followed a statement by Turkey’s Foreign Ministry earlier in the week in which it urged other nations to recognize the coalition.
That statement was meant to convey that Turkey itself recognized the new group, but it was not widely reported that way.
Meanwhile, the Pentagon has told the Obama administration that any military effort to seize Syria’s stockpiles of chemical weapons would require upward of 75,000 troops, amid increasing concern that the militant group Hezbollah has set up small training camps close to some of the chemical weapons depots, according to senior US officials.
The estimated size of the potential effort, provided to the White House by the military’s Central Command and Joint Staff, stunned top administration officials.
It called into question whether the United States would have the resources to act quickly if the movement of chemical weapons forced President Obama, as he said in August, to ‘‘change my calculus’’ about inserting US forces into the most brutal civil conflict to emerge from the Arab uprisings. So far Obama has avoided direct intervention.
The Pentagon has not yet been directed to draft detailed plans of how it could carry out such a mission, according to military officials.
There are also contingency plans, officials say, for securing a more limited number of the Syrian chemical weapons depots, requiring fewer troops.
Turkey, along with Arab and Western countries, had pressured the Syrian political opposition, which had been seen as fractious and ineffectual, to realign itself as a broader coalition that included more officials from within Syria, which it did Sunday after several days of wrangling in Doha, Qatar.
Turkey’s support for the Syrian rebels has become a domestic issue for the government of Prime Minister Recep Tayyip Erdogan, which is facing a backlash from its own public over the mounting toll of the war because the fighting has brought cross-border trade to a halt and the influx of refugees has raised tensions.