AMMAN, Jordan -- Syrian President Bashar Assad made a rare public appearance at a Damascus power station on Wednesday, while two bombs exploded near the city centre, killing one and wounding over two dozen people, Syria's state news agency reported.

Footage of the visit broadcast on state television showed Assad chatting casually with a group of employees, two days after his prime minister narrowly escaped assassination by an explosion and a day after another major bombing in the capital took the lives of at least 14.

SANA said a 10-year-old boy was killed and 28 people wounded, some seriously, in Wednesday's attack, when improvised explosive devices went off in Khaled Bin Walid street and the nearby Bab Mesalla square. It said the bombs were planted by "terrorists," a term the government uses to describe rebels fighting to topple the Syrian leader.

The Britain-based Syrian Observatory for Human Rights however said the Bab Mesalla explosion was near a police station and due to rocket fire. It said the blast left casualties but did not have figures on dead or wounded. It also said that several people, including children, were wounded in the explosion in Khaled Bin Walid street.

Police had sealed off Bab Mesalla, which has restaurants, shops and a main public transportation station linking Damascus with the southern provinces of Daraa and Sweida, the Observatory added.

Assad's visit to the Umayyad Electrical Station in the Tishrin Park district came on International Workers Day, or May Day. State TV showed the Syrian leader, confident and wearing a dark business suit, addressing the station's staff and later shaking their hands. Similar still images also appeared on a page used by the Syrian presidency on the popular social network Facebook.

"They want to scare us, we will not be scared ... They want us to live underground, we will not live underground," Assad told a group of workers who had gathered around him. "We hope that by this time next year we will have overcome the crisis in our country," he added.

Tuesday's blast was the second in the heart of the capital in two days. Rebels seeking to topple Assad have been trying to create a supply line from Jordan, so that arms bought by Saudi Arabia and Qatar can be shipped in for assaults on the city they hope to capture.

Meanwhile, the Egypt-based Syrian National Coalition rebuked the leader of Lebanon's Hezbollah militant group, in its first public response a day after he said that Syrian rebels will not be able to defeat Assad's regime militarily.

Sheik Hassan Nasrallah had warned that Syria's "real friends," including his Iranian-backed militant group, could intervene on the government's side if the need arises.

The coalition said it hoped Hezbollah would stay out of the Syrian war, and urged Lebanon to "control its borders and urgently stop, through all available means, the military operations attributed to Hezbollah in areas close to the Syrian border."

It also blamed Assad's regime for "destroying" religious Muslim and Christian sites.

Hezbollah, a powerful Shiite Muslim group, is known to be backing Syrian government forces in Shiite villages near the Lebanese border against the mostly Sunni rebels fighting to topple Assad. But Nasrallah's comments were the strongest indication yet that his group is ready to intervene more substantially on the side of Assad's embattled regime.

"You will not be able to take Damascus by force and you will not be able to topple the regime militarily. This is a long battle," Nasrallah said, addressing the Syrian opposition. "Syria has real friends in the region and in the world who will not allow Syria to fall in the hands of America or Israel or the Takfiris."

Takfiris is a term used to refer to followers of an al-Qaeda-like extremist ideology.

Hezbollah and Iran are close allies of Assad. Rebels have accused both of them of sending fighters to assist Syrian troops trying to crush the 2-year-old anti-Assad uprising, which the UN says has killed more than 70,000 people.