Al Qaeda Leader, Somalia-Based Terror Group Present New Messages

Familiar terrorist groups, familiar threats, familiar boasts and grievances - all in new messages tied, either directly or indirectly, to al Qaeda.

Two videos and one audio link have come to light in recent days that suggest that the world's most recognizable terrorist group is still active, at least in online postings.

The audio is a question-and-answer session purportedly involving al Qaeda leader Ayman al-Zawahiri that was published Friday on the radical Islamist website Hanein. While CNN has not verified the authenticity of the tape, the voice is similar to al-Zawahiri's from previously authenticated recordings.

In a wide-ranging, nearly hour-long interview with al Qaeda's media arm, known as al-Sahab, al-Zawahiri touches on everything from drones to Syria to Egypt. He insists that al Qaeda is holding strong 13 years after the United States launched its 'war on terror' following the September 11, 2001, attacks.

'The upper hand is for the one who does not withdraw from his land,' al-Zawahiri says. 'Who has withdrawn from Iraq, and who has not? Who has withdrawn from Afghanistan and who has not?'

Al-Zawahiri adds that even U.S. President Barack Obama knows al Qaeda 'is expanding.'

'Al Qaeda is scattered in all the Islamic world and among the oppressed,' he said.

That analysis is relatively peaceful compared with the chilling words uttered in a newly discovered video from Al-Shabaab.

Among its threats: 'We will blow you up, until we finish you off.'

Members of the Somalia-based, al Qaeda-linked militant group also use the video to reflect on one of its most memorable, deadliest attacks to date - the four-day siege last September of an upscale Nairobi, Kenya, indoor shopping center that ended with at least 67 killed.

That Westgate Mall attack may have been one of the bloodiest tied to Al-Shabaab, but it won't be the last, men featured on the video suggested.

'It's not that Westgate was enough,' they say. 'There are still hundreds of men who are wishing for such an operation.'

Peter Bergen, an authority on terrorism who interviewed the late Osama bin Laden and is a CNN national security analyst, said that this Al-Shabaab threat has to be taken seriously.

'We certainly can't dismiss their ability to carry out those kinds of terrorist attacks,' Bergen said.

The two messages come on the heels of another one that got attention this week showing what looks like the largest and most dangerous gathering of al Qaeda in years.

In the middle of that video clip, the man known as al Qaeda's crown prince, Nasir al-Wuhayshi, appears brazenly out in the open, greeting followers in Yemen. Al-Wuhayshi is the No. 2 leader of al Qaeda globally and the head of al Qaeda in the Arabian Peninsula, or AQAP, which is considered the most dangerous al Qaeda affiliate.

In a speech to the group, al-Wuhayshi makes it clear that he's going after the United States, saying 'We must eliminate the cross. The bearer of the cross is America!'

The video started appearing on jihadist websites recently, drawing the attention of U.S. officials and global terrorism experts. U.S. officials say they believe it's authentic.

They believe the highly produced video is recent. With some fighters' faces blurred, there is worry it signals a new round of plotting.

CNN