Syrian tanks Wikipedia Commons Both Turkey and Syria have reportedly sent troops to their shared border in the aftermath of the downing of a Turkish jet last week.

Yesterday Al Arabiya reported that Turkey was deploying troops and at least 30 Turkish military vehicles equipped with anti-aircraft rocket launchers to the border, straight west of Aleppo — Syria's largest city — as a precautionary measure after one of its jets was shot down on June 22 after the jet had strayed into Syrian airspace for five minutes.

Today Free Syria Army (FSA) General Mustafa al-Sheikh, head of the association of senior officers who defected from President Bashar al-Assad's forces (i.e. Higher Military Council), told Reuters that about 170 Syrian tanks had assembled north of Aleppo, about 19 miles from the Turkish border.

Rebels told Reuters that last night Syrian helicopter gunships bombarded a strategic town in northern Syria overnight and tanks closed in on Aleppo, but stayed away from the new Turkish defenses on the border.

All of this comes at a time when the violence and tempo of the conflict is increasing as June 21 marked the deadliest day since the U.N.-backed ceasefire came into force on April 12 and Syrian insurgents have been increasingly effective as they have struck three high-profile targets this week.

On Tuesday al-Assad told government officials that they "live in a real state of war from all angles" and that "all policies and all sides and all sectors need to be directed at winning this war."

About 3,000 civilians and opposition fighters have been already killed so far this month, according to Britain-based expatriate group Syrian Observatory for Human Rights.

On June 22 Syria shot down an unarmed, Turkish two-seat F-4 Phantom jet — Turkish Deputy Prime Minister Bulent Arinc said it was a reconnaissance aircraft — over the Mediterranean. Turkish Prime Minister Recep Tayyip Erdogan accused Syria of a “hostile” and “heinous attack” in shooting down the army jet without warning and ordered his troops near the border to treat any approaching Syrian military element approaching as a military target.

Turkey claimed that Syria also shot at one of the search and rescue planes that were looking for the downed jet's two pilots. Investigators eventually found two pairs of boots and two helmets near the wreckage but no pilots.

Turkey subsequently appealed to NATO under Article 4, which deals with what happens when the "territorial integrity, political independence or security of any of the Parties is threatened," and pushed the international community to consider the incident as an attack on the whole military alliance.

Western officials, including U.S. Secretary of State Hillary Clinton and British Foreign Minister William Hague, strongly condemned Syria's actions while UN accuses Assad-directed Syrian forces of killing more than 10,000 people during the conflict.

Western- and Arab-backed efforts to form a joint diplomatic approach with Russia have so far failed while all sides agree that Turkish military intervention would require full NATO support.

Turkey shelters the rebel Free Syria Army and hosts 32,000 Syrian refugees on its southeastern border with Syria (i.e. about 30 miles from where the Turkish jet was shot down). It denies providing arms for the insurgents, but the U.S. and Arab states have provided rebels with "non-lethal communication equipment and other technical assistance" and there are reports that the U.S. sent mercenaries to fight with the insurgency.

Over the weekend Syria said that it had killed several "terrorists" infiltrating from Turkey.