BEIRUT, Lebanon - In his first interview since December, Syrian President Bashar al-Assad insisted Tuesday that his regime is fighting back against foreign mercenaries who want to overthrow him, not innocent Syrians aspiring for democracy in a yearlong uprising.

The interview with Russian TV showed Assad is still standing his ground, despite widespread international condemnation over his deadly crackdown on dissent.

"There are foreign mercenaries, some of them still alive," Assad said in an interview broadcast Wednesday on Russian state news channel Rossiya-24. "They are being detained, and we are preparing to show them to the world."

Assad also cautioned against meddling in Syria, warning neighboring nations that have served as transit points for contraband weapons being smuggled into the country that "if you sow chaos in Syria you may be infected by it yourself."

A group known as the Free Syrian Army is determined to bring down the regime by force of arms, targeting military checkpoints and other government sites.

A U.N. observer team with more than 200 members has done little to quell the bloodshed, and some members even have been caught up in the violence themselves.

Six observers had to be evacuated from a northern town controlled by the opposition Wednesday, a day after a roadside bomb hit their convoy and left them stranded overnight with rebel forces. None of the observers was wounded, and it was not clear who was behind the attack.

The shooting started as the convoy arrived in the opposition area, said Ahmad Fawzi, spokesman for international envoy Kofi Annan.

Fawzi said people who had gathered around the observers ducked behind the vehicles, and according to one observer apparently some people were injured when the bomb exploded.

When the shooting subsided, he said, the observers left their vehicles and walked to a Free Syrian Army location where they spent the night.

The United Nations said the team was treated well during its stay with rebels and returned to its base in Hama on Wednesday.