ISTANBUL — Movements of troops and armored vehicles along Turkey’s border with Syria are linked to rising tension following Syria’s downing of a Turkish jet last week, a Turkish government official said Thursday.

The apparent bolstering of its border force comes only two days after Turkish Prime Minister Recep Tayyip Erdogan said his country was changing its military rules of engagement.

It now will treat a military approach toward its borders by Syria as a potential threat that “will be dealt with accordingly,” he said.

“It seems that this is an implication of what the prime minister said in his speech,” the official, who asked not to be named because he is not authorized to speak on the record, told CNN when questioned on reports of troop movements in the border area.

A man from the border village of Guvecci, who asked not to be named for security reasons, told CNN that personnel had been arriving for the past two or three days.

“They are coming in military vehicles. We hear that such transfers are taking place to all border stations,” he said.

Turkish state TV channel TRT gave details of military convoy movements in border areas on its website Thursday, saying trucks loaded with tanks had been moved to a military unit on the border with Syria.

“There were also air-defense systems among the military transfer of military vehicles and tanks,” it reported.

The semi-official Anatolia news agency also reported the transfer of armored vehicles to military posts in some districts of Sanliurfa and Hatay, along the border, on Wednesday.

Relations between the two countries, already strained, have worsened significantly since Syria shot down a Turkish F-4 Phantom jet last Friday.

Both sides say the jet strayed into Syrian airspace, but Turkey says the incursion was accidental and quickly corrected.

Syria’s response drew sharp condemnation from NATO, but the alliance did not promise any action in response to the incident. NATO Secretary General Anders Fogh Rasmussen said Turkey did not invoke the NATO article calling for collective defense of members.

Both countries are searching for the jet’s pilots.

Turkey’s chief of general staff said in an online statement Thursday that an area measuring 70 miles by 23 miles has been scanned, “however neither our pilots nor the wreckage of the plane have been reached so far.”

Some parts of the plane and some items belonging to the pilots have been found, however, the statement said.

Five military vessels, a plane and four search-and-rescue helicopters have been involved in the around-the-clock search since the plane was lost, it said. In addition, a Navy hydrographic survey ship started a deep water search Tuesday.

A Syrian official said Wednesday his country’s forces might have thought the Turkish jet it downed was from Israel.

“As you know, there is a country called Israel there and, as you know, this Zionism country’s planes are very similar. And because they both are from the same factory, from the U.S., maybe Syria thought it was an Israeli plane,” Syrian Information Minister Omran Al Zubi told the Turkish A Haber channel.

Speaking Tuesday in Ankara, Erdogan stressed that his country isn’t an aggressor but will respond bluntly to threats.

“I express this at every opportunity: We never have our eyes on any country’s lands. We don’t show a hostile attitude against any country. We never threaten the security of any country,” he said in remarks aired on CNN Turk.

“We never hesitate to respond in the harshest way and do what is necessary with all our existing power, as well as with the power and inspiration that we get from our history, against hostile attitudes, attacks and threats against us.”

Syria raised the stakes Monday in the war of words over the incident.

Foreign Ministry spokesman Jihad Makdissi said the plane was shot down in Syrian airspace, disputing Turkey’s claim that it was downed over international waters after briefly straying into Syrian airspace by mistake.

“What happened was a violation of Syrian airspace. Even Turkey says Syrian sovereignty was violated. Regardless of whether it was a training mission, a reconnaissance mission, it was a violation,” Makdissi said.

— CNN’s Ivan Watson contributed to this report.