The United States and Germany are sending Patriot missiles and troops to the Turkish border, a warning to Syria's besieged President Bashar al-Assad.

The surface-to-air interceptors would be "dealing with threats that come out of Syria," said U.S. Defense Secretary Leon Panetta. Threats would include Syrian strikes inside Turkey and fighting between the government and rebels that extends into Turkey.

Errant Syrian artillery shells struck the Turkish border town of Akcakale and killed five Turkish civilians in October.

"We can't spend a lot of time worrying about whether that pisses off Syria," said Panetta after signing the order Friday. He spoke after arriving Friday at Turkey's Incirlik Air Base, a U.S. Air Force installation about 80 miles from Syria's border.

Despite the prospect of U.S. missiles on Al-Assad's doorstep and a weakening regime, U.S. intelligence officials said the Syrian leader is showing no signs of giving up.

The deployment includes two Patriot missile batteries, used solely for defensive purposes, and 400 U.S. troops to operate them.

The United States and NATO hope to have them in place by the second week in January, and a military advance team is going in in the next several days, CNN has learned.

The moves come a week after NATO foreign ministers approved the deployment of Patriots to protect Turkey against any threats from al-Assad's regime, rapidly weakening by rebel advances.

Also Friday, the German parliament approved the deployment of German Patriot anti-aircraft missiles to Turkey, with 461 Bundestag deputies voting in favor of the deployment, 86 against and eight abstentions.

The Netherlands have shown willingness to add Patriot batteries, NATO said Friday, to defend Turkey and "de-escalate the crisis on NATO's southeastern border."

Patriots are constructed to take out threats from warplanes and tactical ballistic missiles to unmanned aircraft by impacting with them in midair, according to Raytheon Co., which builds them. The U.S. military used to take out Scud missiles during the Iraq war.

The United States has accused Damascus of launching Scud-type artillery from the capital at rebels in the country's north. One Washington official said missiles came close to the border of Turkey, a NATO member and staunch U.S. ally.

Syria's government called the accusations "untrue rumors" Friday, according to state news agency SANA. Damascus accused Turkey and its partners of instigating rumors to make the government look bad internationally.

NATO has also said it detected what appeared to be ballistic missile launches within Syria and condemned their possible use as "utter disregard for the lives of the Syrian people."

Turkey and NATO insist the Patriot system would be used only for defense.

Al-Assad is 'weakening'

Al-Assad's departure is the dream of his opponents.

U.S. officials said the Syrian president's control is crumbling at an accelerating pace

"It's at its lowest point yet," said one senior US official with direct knowledge of the latest assessments. U.S. intelligence believes the decline has accelerated in recent weeks. "The trend is moving more rapidly than it has in the past."

The officials agreed to talk on the condition their names not be used because they were not authorized to discuss the information with the media.