ISTANBUL — Turkey made it clear on 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 al-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.