In an interview scheduled to be televised on Monday, Pakistani journalist Hamid Mir said Ayman al-Zawahri claimed that "smart briefcase bombs" were available on the black market.
It was not clear when the interview between Mir and al-Zawahri took place.
U.S. intelligence agencies have long believed that al-Qaida attempted to acquire a nuclear device on the black market, but say there is no evidence it was successful.
In the interview with Australian Broadcasting Corp. television, parts of which were released Sunday, Mir recalled telling al-Zawahri it was difficult to believe that al-Qaida had nuclear weapons when the terror network didn't have the equipment to maintain or use them.
"Dr Ayman al-Zawahri laughed and he said `Mr. Mir, if you have $30 million, go to the black market in central Asia, contact any disgruntled Soviet scientist, and a lot of ... smart briefcase bombs are available,'" Mir said in the interview.
"They have contacted us, we sent our people to Moscow, to Tashkent, to other central Asian states and they negotiated, and we purchased some suitcase bombs," Mir quoted al-Zawahri as saying.
Al-Qaida has never hidden its interest in acquiring nuclear weapons.
The U.S. federal indictment of bin Laden charges that as far back as 1992 he "and others known and unknown, made efforts to obtain the components of nuclear weapons."
Bin Laden, in a November 2001 interview with a Pakistani journalist, boasted having hidden such components "as a deterrent." And in 1998, a Russian nuclear weapons design expert was investigated for allegedly working with bin Laden's Taliban allies.
It was revealed last month that Pakistan's top nuclear scientist had sold sensitive equipment and nuclear technology to Iran, Libya and North Korea (news - web sites), fueling fears the information could have also fallen into the hands of terrorists.
Earlier, Mir told Australian media that al-Zawahri also claimed to have visited Australia to recruit militants and collect funds.
"In those days, in early 1996, he was on a mission to organize his network all over the world," Mir was quoted as saying. "He told me he stopped for a while in Darwin (in northern Australia), he was ... looking for help and collecting funds."
Australia's Attorney-General Philip Ruddock said the government could not rule out the possibility that al-Zawahri visited Australia in the 1990s under a different name.
"Under his own name or any known alias he hasn't traveled to Australia," Ruddock told reporters Saturday. "That doesn't mean to say that he may not have come under some other false documentation, or some other alias that's not known to us."
Mir describe al-Zawahri as "the real brain behind Osama bin Laden."
"He is the real strategist, Osama bin Laden is only a front man," Mir was quoted as saying during the interview. "I think he is more dangerous than bin Laden."
Al-Zawahri — an Egyptian surgeon — is believed to be hiding in the rugged region around the Pakistan-Afghan border where U.S. and Pakistani troops are conducting a major operation against Taliban and al-Qaida forces.
He is said to have played a leading role in orchestrating the Sept. 11, 2001, attacks on the United States.
