The White House denied charges Tuesday that it tried to sabotage Jimmy Carter's trip to Cuba by dropping a story about the Communist nation's bioweapons capabilities in advance of the former president's trip there.

Carter arrived in Cuba Sunday for the first visit by a U.S. head of state, in or out of office, since Calvin Coolidge went to the island nation in 1928. On Monday, he visited a biotechnology lab, after which he said the State Department did not provide evidence to him about Cuba's capacity to produce biological weapons.

Upon Carter's arrival, Cuban President Fidel Castro told the 39th president —who ordered the 1980 Cuban boatlift allowing tens of thousands of Cubans to flee the repressive regime — that he would have free access to any facility on the island, including biotechnology laboratories, and could express himself freely, "whether or not we agree with part of what you say, or with everything you say."

Carter, along with delegates from the Carter Center, visited a major biotechnology lab Monday, the Center of Genetic Engineering and Biotechnology, on the outskirts of Havana. He later released a statement complimenting the Cuban medical community on its advanced medical care. He also reluctantly addressed allegations Cuba could be involved in bioterrorism.

"In preparation for this unprecedented visit, I requested, and we all received, intense briefings from the State Department, the intelligence agencies of my country, and high officials in the White House. I asked them specifically on more than one occasion is there any evidence that Cuba has been involved in sharing any information to any other country on Earth that could be used for terrorist purposes. And the answer from our experts on intelligence was 'no,'" Carter said.

Carter's statement — meant to address a flurry of claims and counter-claims last week between the U.S. State Department and Cuba over biological weapons programs — prompted the Bush administration to stand by its charges that Cuba may be seeking to spread bioweapons. Cuba last week dismissed the charges as "loathsome."

White House Press Secretary Ari Fleischer said that Carter did speak with National Security Adviser Condoleezza Rice prior to his departure but the issue of "bioweaponry did not come up." Instead, the two spoke about human rights concerns that the administration wanted Carter to raise during his trip.

However, Fleischer said, the administration raised concerns about Cuba's ability to share dual-use technology with other rogue nations as far back as March, when Assistant Secretary of State Carl Ford testified on Capitol Hill about Cuba's biotechnological capabilities.

Secretary of State Colin Powell said Monday he does not know who from the State Department briefed Carter, but he stood by Undersecretary of State John Bolton's statements last week that Cuba has the "capacity" to develop such arms. 

Bolton told an audience at the policy center The Heritage Foundation that "Cuba has provided dual use biotechnology to other rogue states. We are concerned that such technology could support biological warfare programs in those states."  Powell said he doesn't think Bolton said Cuba has the weapons, but it has the potential.

Carter said Monday that he was impressed with Cuba's medical community and saw no evidence of bioweapons technology. Fleischer said Tuesday that that type of technology is easy to hide.

The administration is hoping that Carter will turn his attention to human rights during his trip. Already, Carter has met with two Cuban political dissidents who are coordinating a petition drive in hopes of forcing the Cuban government to allow greater freedom, including guarantees of individual freedoms, an amnesty for political prisoners, electoral reforms, and the right to own their own businesses. 

On Tuesday, he visited AIDS patients. Cuba has the lowest per capita AIDS rate in all of Latin America, with 28 cases per million inhabitants.

Carter told a group of students Monday night that he would address "the differences in our approach to the form of governments we have" in a major foreign policy address to be aired Tuesday night in a live radio broadcast.  Castro has promised that he would let the speech go on without censor.

The Associated Press contributed to this report.