NEW YORK, Nov. 1 (Xinhuanet) -- A trial questioning the practice of random bag searches in New York city's transit system continues in Manhattan Federal Court Tuesday, with a senior official in charge of counter-terrorism testifying for the defense.

    In his testimony, Deputy Commissioner of Counter-terrorism Mike Sheehan of the city's police department said while the searches are not 100 percent effective, they work well with other policies to warn terrorists that it is simply too risky to attack New York City.

    Gail Donoghue, an attorney for the city, said Commissioner Sheehan's testimony demonstrated how a counter terrorism program works and how the different programs are grouped in a city like New York. "They work in a variety of ways. The regimen changes from day to day, all to enhance the sense that the city is being watched and the city is being kept secure."

    He said given the way that the container search program is set up, the certainty is very high that a terrorist could avoid a checkpoint and go to another.

    The ongoing lawsuit, brought by the New York Civil Liberties Union(NYCLU), challenges the searches on behalf of five plaintiffs. The group argues that the bag checks will not prevent a terrorist attack, and instead they violate the New York State constitution because they could lead to racial profiling.

    Gene Russianoff from the Straphangers Campaign is expected to testify for the NYCLU.

    The searches were put in place on city subways and buses in July, after the deadly subway bombings in London. The city authorities maintain that the policy is a valuable tool in preventing terrorism.

    Wednesday is expected to be the last day of witness testimony. Enditem