DAMASCUS, May 18 (Reuters) - Syria's defence minister has called on small armed groups that have yet to merge with the security apparatus to do so within 10 days or face unspecified measures, in a bid to consolidate state authority six months after Bashar al-Assad was toppled.

A plethora of weapons outside government control has posed a challenge to interim President Ahmed al-Sharaa's efforts to establish control, as groups that both back him and oppose him remain armed.

The statement did not seem aimed at the U.S.-backed Syrian Democratic Forces (SDF), a large Kurdish-led force in the northeast that signed an agreement with Sharaa earlier this year aimed at integration with state institutions.