America now faces a national security challenge of extraordinary complexity.

Iraqi authorities are now confronting the security challenge of the last several weeks.

Certain details also underscore national security challenges for the new Bush administration.

The security challenges we face, terrorism above all, will be with us for many years.

If a legitimate government emerges in Iraq, we will quickly face two security challenges there.

New Zealand is able to meet future national security challenges.

Next, the couples compete in the most important security challenge yet.

Flash drives may present a significant security challenge for some organizations.

It is perhaps the most important security challenge facing us in the next century.

He himself has called the vote a potential security challenge.