"It is certain there will be NATO issues and other security issues at this meeting," said Daniel Vaarik, a spokesman for Kallas. "We are about to join NATO so this is a very vital time for us."
Bush extended the invitation to Kallas on Aug. 12.
The Estonian daily Postimees reported that Bush invited Kallas to the White House to sign a deal granting U.S. soldiers immunity from prosecution for war crimes in the new International Criminal Court, which Estonia has joined. The United States has worked out agreements with some countries belonging to the court that grant immunity for U.S. soldiers in exchange for military aid.
But Vaarik said this was not the point of Kallas' visit.
"The subject may arise during the meeting, but so far there are no agreements on signing any documents at the top level," he said.
The United States has approached Estonia with a proposal for signing a bilateral agreement on the new war crimes court, but that proposal is being studied by legal experts and the government has not made a decision on it, he said.