BEIRUT -- Syria's president on Wednesday accused the West of backing al Qaeda in Syria, warning it will pay the price "in the heart" of Europe and the United States as the terror network becomes emboldened.

Bashar Assad spoke in an interview set to be aired later Wednesday on the government-run Al-Ikhbariya channel, marking Syria's independence day. Excerpts of the interview were broadcast in advance and posted on his office's Facebook page.

"Just as the West financed al Qaeda in Afghanistan in its beginnings, and later paid a heavy price, today it is supporting it in Syria, Libya and other places and will pay the price later in the heart of Europe and the United States," Assad said.

In the excerpts, Assad offered no evidence to back his charge that the U.S. was now backing the international terror group that knocked down the World Trade Center in New York and hit the Pentagon on Sept. 11, 2001.

Extremist groups such as the al Qaeda-affiliated Jabhat al-Nusra are gaining ground in Syria's two-year civil war. The conflict began with largely peaceful protests demanding reforms and eventually turned into an insurgency and war in response to a brutal military crackdown on the protesters. More than 70,000 people have been killed, according to the United Nations.

Assad's regime says the uprising against him is a conspiracy carried out by foreign-backed extremists, blaming the violence on "armed gangs" and al Qaeda-backed terrorist groups.

Jabhat al-Nusra, or the Nusra Front, has emerged as the most effective force among the mosaic of rebel units fighting to topple Assad.

Last week, Nusra Front leader Abu Mohammad al-Gonali pledged allegiance to al Qaeda's leader, Ayman al-Zawahiri, in an audio message.

In the TV interview, Assad also lashed out at Jordan, accusing his southern neighbour of allowing "thousands" of fighters to enter Syria across its borders.

Regional officials and military experts said recently that weapons shipments to opposition fighters by Arab governments have increased sharply, in co-ordination with the U.S., in the hopes of readying a rebel push into Damascus. Jordan opened up a new route for the weapons late last year.

Assad's rare TV interview came as his military fought to reverse rebel advances across much of the country. A rocket attack by his military Wednesday killed at least 12 people in a central village.