NATO Secretary-General Anders Fogh Rasmussen says Syria's government is "approaching collapse" and urges President Bashar al-Assad to stop fighting and accommodate a political transfer of power.

Those comments came as a debate was ranging about the use of scud missiles in Syria.

A U.S. official said American military satellites picked up and confirmed the infrared signature of four short-range Scud missiles launched from the Damascus area to northern Syria in the past several days.

The missiles did not land on the Turkish side of the border but "came close," he said.

But on Thursday a Syrian foreign ministry official categorically denied the reports about the Syrian military using Scud missiles against rebel groups on Syrian state TV.

Read more on the conflict in Syria:

Syria hits 'propaganda'

Teen risks life to rescue stranger

On the trail of chemical weapons