Turkey's foreign minister says the country has barred its air space to Syrian civilian flights, as tension between the two countries continues to escalate.

Ahmet Davutoglu said Sunday that Turkey had made the decision because the Syrian regime, which is battling an insurgency, was "abusing" civilian flights by transporting military equipment.

He says Syria's government was notified of the decision on Saturday.

Last week, Turkey forced a Syrian plane, departing from Russia, to land and reportedly confiscated military equipment on board. Russia said the plane was carrying spare radar parts.

Syria had announced Saturday it was closing its air space to Turkish flights.

After a week of exchanges of fire across the volatile border, aTurkish newspaper reported that Turkey has reinforced four naval bases along its Mediterranean coast north of Syria.

In an unattributed report, the Hurriyet daily said Turkey sent frigates with cannons, as well as anti-ship and anti-aircraft missiles to the naval bases.

Turkey has been retaliating for Syrian shells and mortar rounds hitting Turkish soil.

Despite Turkey's recent measures, Syrian opposition leaders say Ankara and other foreign backers of the rebels are not doing enough to help them break the battlefield stalemate.

Abdelbaset Sieda, head of the largest opposition group, the Syrian National Council, said the international community is doing nothing more than managing the Syrian conflict.

The international community must establish safe havens in Syria and enforce no-fly zones to help the rebels counter the regime's airstrikes on rebel-held areas, Sieda told reporters in Istanbul, Turkey.

This would also cut down on the number of Syrians seeking refuge abroad and "resolve the humanitarian crisis, especially with winter approaching," he said.