Alarmed by the assassination of two Iraqi officials, Bush administration officials are warning of increasing violence as the June 30 transfer of political power nears.

Insurgents and Saddam Hussein's loyalists are stepping up efforts ahead "to shake the will" of the new government, the U.S.-led coalition and the Iraqi people, President Bush's (search) national security adviser said Sunday.

"They're not going to succeed," Condoleezza Rice (search) said in a televised interview.

The weekend assassinations "are very sad events when Iraqi patriots are gunned down by these traitors and by these terrorists," Rice said. "And indeed, there will continue to be violence, because these are people who have no future in a free Iraq."

Kamal al-Jarah (search), an Education Ministry official in charge of contacts with foreign countries and the United Nations, was killed Sunday outside his home.

On Saturday, an Iraqi deputy foreign minister, Bassam Salih Kubba (search), was killed as he was driving to work.

Even with U.S. troops and private contractors aiding Iraqi security forces, "It's going to be a dangerous period," Secretary of State Colin Powell (search) told "Fox News Sunday."

"It's hard to protect an entire government," he said.

The United States hopes the establishment of a sovereign Iraqi government will undercut the insurgency, allowing security to improve so that balloting for an elected administration can be held in January.

Powell said "the real solution to the security problem" is for Iraqi forces to be trained quickly. The United States is working diligently to accomplish that, he said.

The new government will take control of the Abu Ghraib prison, at the heart of the prisoner abuse scandal, but the facility will not be torn down, interim Iraqi President Ghazi al-Yawer said. Bush has suggested destroying it as "a fitting symbol of Iraq's new beginning."

"If we consider it's a symbol of Saddam's atrocities, Saddam used to torture people in each and every basement in Iraq, so that means we have to demolish all government entities. That's unwise," al-Yawer told ABC's "This Week."

"This is very reactionist. We are people that we need every single dollar we have, in order to rebuild our country, instead of demolishing and rebuilding," he said.

About 150,000 U.S. and other coalition troops will remain in Iraq after June 30 to held with security, under a resolution approved unanimously by the U.N. Security Council last week.

Bush, at an economic summit last week on Sea Island, Ga., discussed the possibility of an expanded role for NATO in Iraq.

Sixteen of the 26 NATO members have troops in Iraq and the alliance provides logistical help for a Polish-led division in the country.

The Bush administration would like the alliance to take on additional duties, such as training Iraqi's new army and sending more troops. But officials recognize that is unlikely, given strong German and French opposition.

"I don't think the president ever implied, nor should any of us think, that there are large bodies of NATO troops that are sitting around waiting to go somewhere. There are not," Powell said.

NATO leaders will talk about the alliance's role in Iraq during a summit in Turkey at month's end.

As for the fate of Saddam, al-Yawer said the United States would transfer custody of the former president after June 30, "given that we can make sure we can protect him" until a trial this summer. Saddam has been held in an undisclosed location since his Dec. 13 capture by U.S. forces.