Syrian President Bashar Assad called on his army Monday to increase readiness to cope with "regional challenges." The president's comments came during an annual address to the military but also as the campaign in Lebanon entered their 20th day of fighting. Travelers from Syria have reported that some reservists have been called up for military duty - a sign that Syria is concerned the fighting in Lebanon could spill over. The Syrian government has not made any announcement about calling up reserves. "The anniversary of the founding of the army comes this year in view of international circumstances and regional challenges that require caution, vigilance, preparation and readiness," Assad said in a statement carried by the official Syrian Arab News Agency. Assad called on all formations and units of the armed forces "to intensify efforts in training and to work for more preparations and raise readiness," according to the statement. "We must be aware that every effort and every drop of sweat exerted in training now will spare a drop of blood when the time comes," he said. Syria so far has stayed out of the Lebanon conflict, but Israeli airstrikes have increasingly come closer, with repeated raids on the Beirut-Damascus highway that links Lebanon and Syria. In a warning to Israel four days after the fighting erupted, Syria's government promised a firm and immediate retaliation for any possible Israeli attack on its territory. Assad said Syria was more determined to support Lebanon and will not flinch under international pressure. "All the threatening cries by the forces of hegemony that is backing the aggression will not hold us from continuing the course of liberation and supporting our brothers and the [Hizbullah] resistance," he said.