11.   It has been suspected for some time that North Korea has been working on a nuclear device.

12.   Although nuclear war is still an important concern, the security threat has expanded to include crude nuclear devices, chemical and biological weapons and radiological devices.

13.   Any of these targets could be assailed with a weapon of mass destruction, such as a chemical agent, nuclear device or deadly pathogen.

14.   Another possibility is that the Indians and Pakistanis may have deliberately conducted subcritical blasts to test parts of nuclear devices, rather than full-fledged bombs.

15.   At almost the same time, Indian officials were announcing the detonation of two additional nuclear devices in another round of weapons testing.

16.   At the same time, US officials at the United Nations tried to persuade members of the Security Council to chastise India for testing five nuclear devices since Monday.

17.   Authorities suspect that terrorist groups have tried to gain access to nuclear devices that could be smuggled in a suitcase.

18.   Administration officials cryptically discussed incentives that the United States might offer Pakistan not to detonate a nuclear device.

19.   Both nations exploded nuclear devices despite international pleas against it.

20.   But Chinese officials continued to reiterate their opinion that India had touched off the crisis by testing its own nuclear devices earlier this month.