A Syrian threat that Damascus is prepared to use chemical and biological weapons to repel foreign aggressors drew a volley of warnings late Monday from the US and Britain.

“Given the regime’s stockpile of chemical weapons, we will continue to make it clear to Assad and those around him that the world is watching,” US President Barack Obama said, according to media reports. “They will be held accountable by the international community and the United States should they make the tragic mistake of using those weapons.”

In a statement Monday, Syrian Foreign Ministry spokesperson Jihad Makdissi said the regime holds chemical and biological weapons in its arsenals and that it is prepared to use them to defend an external attack but not against its own citizens.

British Foreign Secretary William Hague declared that the use of chemical weapons is “unacceptable” under any circumstances and UN secretary general Ban Ki-moon said such a development would be “reprehensible,” Sky News reported

The Pentagon also cautioned the Syrians to not “think one iota” about using the weapons, Sky reported.

“We will continue to work with our friends and our allies and the Syrian opposition on behalf of the day when the Syrian people have a government that respects their basic rights to live in peace and freedom and dignity,” Obama said according to a USA Today report.

Israel has recently expressed concern that in the mayhem of Syria’s civil war, some stockpiles of chemical weapons could find their way over the border and into the hands of Hezbollah. Israel has said it will take action to prevent such a development.

Syria’s chemical stockpiles are thought to be the largest in the Middle East, and the fourth largest in the world, according to some analysts. They include supplies of sarin and VX nerve agents, as well as mustard gas and cyanide.

On Tuesday, Haaretz reported that only 53 percent of the population have received gas masks, despite a four-year-old drive for the military to distribute them in case of attack.

Sources say bureaucratic wrangling over fully funding the program have left many Israeli unprotected, according to the report.

“We haven’t seen a shekel more than what was planned for in advance,” a military source told the paper.