NEW YORK, March 4 (IslamOnline & News Agencies) - One month after the September 11 attack on the United States, senior U.S. officials were informed that terrorists had obtained a 10 kiloton nuclear bomb and were planning to smuggle it into New York, Time Magazine reported.

In its latest edition Monday, March 4, the London-based Time said the highly classified intelligence alert was circulated to only a few top U.S. officials and was deliberately kept secret so as not to panic New Yorkers, Agence France-Presse (AFP) reported.

The intelligence report was based on information from a U.S. agent codenamed "dragonfire," described as of "undetermined" reliability by intelligence officials, Time added.

However, the alert dovetailed with reports that nuclear devices had gone missing from the Russian arsenal during the 1990s, specifically a report from one Russian general who maintained that his forces were missing a 10-kiloton bomb, Time said.

A 10-kiloton bomb detonated in Lower Manhattan could kill some 100,000 civilians, contaminate 700,000 more with radiation and flatten everything within half-a-mile of the blast, the news weekly reported.

The intelligence alert was so secret that New York's mayor at the time, Rudolph Giuliani, said he was kept in the dark and top FBI officials were also out of the loop, according to Time.

An intensive investigation was launched, and when counter terrorism investigators turned up nothing, they concluded that the information from "dragonfire" was false.

However, the alert drove home continued U.S. vulnerability to terrorism despite increased security following September 11.

"We are as vulnerable today as we were on 9/10 or 9/12," Karen Hughes, White House adviser to President George W. Bush, was quoted as saying. "We just know more."

In the past six months, the U.S. Administration and Congress have mobilized massive amounts of government money, intelligence and personnel to track terrorists at home and abroad and tighten the country's protective net. But all nets have holes.

A Time investigation found some good news – notably that the CIA, FBI and other intelligence and law-enforcement agencies are finally starting to work as a team. But in other critical areas, such as gathering and analyzing intelligence, strengthening homeland security and rounding up Al-Qaeda, the U.S. has yet to solve its most grievous problems.