Searches also will be conducted by Metropolitan Transportation Authority police on suburban commuter trains, Governor George Pataki said. The mayor and governor announced the measures during a news conference on Staten Island.

``I want to emphasize that there is still no threats to this city that have been explicitly made or to our subway or bus system,'' Bloomberg said. ``People should go ahead and feel comfortable in using'' mass transit, he said.

New York stepped up security measures for transportation facilities after the July 7 London subway and bus bombings that killed at least 56 people.

Police Commissioner Raymond Kelly said the new random- search policy would last ``as long as necessary.'' He asked passengers to try to avoid carrying backpacks or large bags.

Kelly said last week that New York is paying overtime to have more officers in subway trains on platforms, at commuter rail terminals, and at bus stops and bridge and tunnel crossings. The U.S. Department of Homeland Security raised the threat level to high from elevated after the July 7 London bombings, making federal funds available to protect major transit systems, Kelly said.

Poll on Terror

A poll of registered New York City voters released yesterday showed that by an 8-to-1 margin New Yorkers have continued their routines even after the July 7 bombings.

Still, the Quinnipiac University Polling Institute poll found 72 percent either ``very worried'' or ``somewhat worried'' about an attack on New York mass transit, compared with 28 percent who were ``not too'' or ``not at all'' worried.

The survey of 1,313 New York City voters conducted July 12- 17 had a margin of error of plus or minus 2.7 percentage points.

The mayor is founder and majority owner of Bloomberg News parent Bloomberg LP.