Russia's envoy to NATO has warned the alliance against reinforcing Turkey's air defences after the Turkish army downed a Russian military jet sparking a major and ongoing diplomatic row.

Alexander Grushko said on Monday that Russia was not certain strengthening the forces would "strictly correspond to the task of neutralising possible challenges from terrorist organisations".

"If by the NATO efforts Turkey tries to contain Russia, this will be an obstacle to the establishment of an international coalition against terrorism," Grushko said, according to Russia's Itar-Tass news agency.

The comments came after NATO allies discussed sending patrol aircraft and Patriot missiles to Turkey - an alliance member.

The country currently hosts only Spanish missiles.

NATO foreign ministers said on Tuesday that measures were likely to include more ships from NATO members in the Eastern Mediterranean, more NATO planes based in the Turkish base at Incirlik and more missile defence batteries in addition to the Spanish ones.

The final plan has not been made to date.

Spat costs

Meanwhile, Turkey's general staff said in a statement on Monday that the country's air force had resumed its patrol operation along the Turkish-Syrian border.

Since November 24, when Turkish fighter jets downed a Russian Su-24M bomber, Turkey had been less active in the near-border area, and there were no reports of cross-border strikes against the Islamic State of Iraq and the Levant (ISIL) group.

Moscow has imposed a series of economic sanctions against Ankara after the incident, sparking the biggest crisis between the two countries since the Cold War.

Turkish deputy prime minister said on Monday that the tensions with Russia could cost Turkey's economy $9bn in a worst-case scenario of "zero relations".

Source: Al Jazeera and agencies