He spoke as Germany's cabinet approved stationing Patriot anti-missile batteries on Turkey's border with Syria, a step requiring deployment of NATO troops that Syria fears could permit imposition of a no-fly zone over its territory.
"Syria stresses again, for the tenth, the hundredth time, that if we had such weapons, they would not be used against its people. We would not commit suicide," Faisal Maqdad said.
US President Barack Obama and other NATO leaders have warned that using chemical weapons would cross a red line and have consequences, which they have not specified.
Assad would probably lose vital diplomatic support from Russia and China that has blocked military intervention in the 20-month-old uprising that has claimed more than 40,000 lives.
A senior Russian lawmaker and ally of President Vladimir Putin said Syria's government is incapable of doing its job properly, a sign that Moscow may already be trying to distance itself from Assad.
"We have shared and do share the opinion that the existing government in Syria should carry out its functions. But time has shown that this task is beyond its strength," Vladimir Vasilyev, who heads President Putin's party group in the State Duma lower house, was quoted as saying by Interfax news agency.
Syria's Maqdad said Western reports the Syrian military was preparing chemical weapons for use against rebel forces trying to close in on the capital Damascus were simply "theater".
"In fact, we fear a conspiracy ... by the United States and some European states, which might have supplied such weapons to terrorist organizations in Syria, in order to claim later that Syria is the one that used these weapons," he said on Lebanon's Al Manar television, the voice of Hezbollah.
"We fear there is a conspiracy to provide a pretext for any subsequent interventions in Syria by these countries that are increasing pressure on Syria."Uncontrollable
Exactly what Syria's army has done with suspected chemical weapons to prompt a surge of Western warnings is not clear. Reports citing Western intelligence and defense sources are vague and inconsistent.
The perceived threat may be discussed in Dublin on Thursday when Russian Foreign Minister Sergei Lavrov and US Secretary of State Hillary Clinton meet international Syria mediator Lakhdar Brahimi to try to put a UN peace process for Syria back on track.
The talks come ahead of a meeting of the Western-backed "Friends of Syria" group in Marrakech next week which is expected to boost support for rebels fighting to overthrow Syrian President Bashar Assad.
Brahimi wants world powers to issue a UN Security Council resolution calling for a transitional administration.
In addition to the possible use of chemical bombs by "an increasingly desperate" Assad, Clinton said Washington was concerned about the government losing control of such weapons to extreme Islamist armed groups among the rebel forces.
US officials said Washington was considering blacklisting Jabhat al-Nusra, an influential rebel group accused by other rebels of indiscriminate tactics that has advocated an Islamic state in Syria and is suspected of ties to al-Qaida.
An explosion in front of the Damascus headquarters of the Syrian Arab Red Crescent killed at least one person on Thursday, Syrian state television said.
It blamed "terrorists from al Qaida" -- a term often employed to refer to rebel forces.
Meanwhile, activists said the army pummeled several eastern suburbs of Damascus, where the rebels are dominant, with artillery and mortar fire. The suburbs have also been cut off from the city's water and electricity for weeks, rebels say, accusing the government of collective punishment.Collapse
Rebels say they have surrounded an air base 4 km from the center of Damascus, a fresh sign the battle is closing in on the Syrian capital.
They also said they were battling soldiers on the road to Damascus International Airport, 20 km out of the capital where several airlines have canceled flights due to security concerns.
Maqdad, in his interview on Thursday, argued that reports of such advances were untrue: "What is sad is that foreign countries believe these repeated rumors."
But residents inside the capital say the sound of shelling on the outskirts has become a constant backdrop and many fear the fight will soon come to Damascus.
The Western military alliance's decision to send US, German and Dutch Patriot missile batteries to help defend the Turkish border would bring European and US troops to Syria's frontier for the first time in the civil war.
The actual deployment could take several weeks.
"Some countries now are now supplying Turkey with missiles for which there is no excuse. Syria is not going to attack the Turkish people," Maqdad said.
But a veteran Turkish commentator, Cengiz Candar of the Radikal newspaper, said Ankara fears Syria's 500 short-range ballistic missiles could fall into the wrong hands.
The government is "of the view that Syria was not expected to use them against Turkey, but that there was a risk of these weapons falling into the hands of 'uncontrolled forces' when the regime collapses," he wrote.
BEIRUT (Reuters) -- Western powers are whipping up fears of a fateful move to the use of chemical weapons in Syria's civil war as a "pretext for intervention", President Bashar Assad's deputy foreign minister said on Thursday.