Turkey will treat any Syrian military units which approach its border as a threat and a military target, Prime Minister Tayyip Erdogan tells parliament.

The move comes after Syria shot down a Turkish plane last week.

Ankara called the incident an act of aggression.

Syrian opposition in exile and Syrian refugees in Turkey welcomed Ankara's toughened rules of engagement.

(SOUNDBITE) (Arabic) SYRIAN NATIONAL COUNCIL SPOKESMAN SAMIR NASHAR SAYING:

"Turkey is behaving in a sensible and patient way. This is the right thing to do and we appreciate its new move against Syria."

Following a meeting in Brussels, NATO member states condemned the incident as "unacceptable" and demanded that Syria ''take all steps'' to prevent the situation from escalating.

Sarah Sheffer, Reuters