The Obama administration bluntly urged the Congress on Thursday to steer clear of directing where terrorism suspects should be prosecuted, pushing back against efforts to require military rather than civilian trials.

A bipartisan group of senators has offered legislation aimed at forcing the administration to prosecute terrorism suspects, like the self-professed mastermind of the September 11, 2001 attacks, Khalid Sheikh Mohammed, in special military commission trials instead of traditional criminal courts.

U.S. Attorney General Eric Holder ordered Mohammed and four alleged co-conspirators to be tried in a criminal court in Manhattan. But concerns by some lawmakers about security costs and granting full legal rights to the suspects have forced administration officials to reconsider.

Holder and Defense Secretary Robert Gates wrote leaders in the House of Representatives to express their opposition to legislation directing how and where to prosecute the cases.

The exercise of prosecutorial discretion has always been and should remain an Executive branch function, they said in the letter to House Speaker Nancy Pelosi and Republican Minority Leader John Boehner.

We believe it would be unwise and would set a dangerous precedent for Congress to restrict the discretion of our departments to carry out specific terrorism prosecutions, Holder and Gates said.

But Boehner spokesman Michael Steel said, The Obama administration isn't listening to the American people, who are saying -- loudly and clearly -- that they don't want dangerous terrorists imported into this country, where they will have the same rights as American citizens.

DISTRACTION FOR OBAMA

The fight over where to prosecute terrorism suspects has become a growing distraction for President Barack Obama's administration, forcing officials to expend political capital fighting legislation that could tie their hands on dealing with terrorism suspects.

Moving forward with the prosecutions is a key part of Obama's plan to close the U.S. military prison at Guantanamo Bay, Cuba, which has been criticized for harsh interrogations of suspects that took place there.

The administration plans to prosecute almost three dozen terrorism suspects held at Guantanamo -- but has not announced where all the trials will be held and in what venues, criminal or military trials.

Holder has said six other detainees will be prosecuted in revamped military commission trials. Those military courts were overhauled to ban the use of coerced testimony and limit the use of hearsay evidence against the suspects.

Obama's fellow Democrats control both the House and Senate, but that has not stopped Congress from imposing limits on moving Guantanamo detainees. The administration must first notify Congress of any moves and offer security assessments.

Representative Lamar Smith, the top Republican on the House Judiciary Committee, offered legislation on Tuesday that would bar bringing any terrorism suspects from Guantanamo to U.S. soil for any purpose, including trial or detention.

It was unclear if the legislation would advance since Democrats control both chambers.

(Editing by Peter Cooney)