WASHINGTON, D.C. — A top State Department security official in Libya told a congressional investigator that he had argued unsuccessfully for more security in the weeks before Ambassador Chris Stevens and three other Americans were killed. Department officials instead wanted to “normalize operations and reduce security resources,” he wrote in an email obtained Tuesday by The Associated Press.

Eric Nordstrom, who was the regional security officer in Libya, also referenced a State Department document that detailed 230 security incidents in Libya between June 2011 and July 2012 that demonstrated the danger there to Americans.

Stevens, a State Department computer specialist and two former Navy SEALs were killed at the U.S. Consulate in Benghazi, Libya, on Sept. 11. U.S. officials initially described the attack as a spontaneous protest over an anti-Muslim Internet video, but later called it a terrorist act.

The Benghazi attack has been grist for the fall presidential election campaign, with Republican nominee Mitt Romney and GOP lawmakers criticizing the Obama administration’s handling of the security situation and its early descriptions of the attack.

Nordstrom is among the witnesses set to testify today before the House Oversight and Government Reform Committee. According to the panel’s chairman, Rep. Darrell Issa, R-Calif., and the head of a subcommittee, Rep. Jason Chaffetz, R-Utah, the State Department refused repeated requests to provide more security for U.S. diplomats in Libya.

Democrats on the Oversight committee were sharply critical of Issa, the chairman.

“The chairman and his staff failed to consult with Democratic members prior to issuing public letters with unverified allegations, concealed witnesses and refused to make one hearing witness available to Democratic staff, withheld documents obtained by the committee during the investigation, and effectively excluded Democratic committee members from joining a poorly-planned congressional delegation to Libya,” the memo said.

The Democrats said that in the previous two years, House Republicans have voted to cut the Obama administration’s requests for embassy security by some $459 million.

The State Department document detailing the 230 incidents spoke of the risk to U.S. diplomats in Libya as well as other Americans.

“The risk of U.S. Mission personnel, private U.S. citizens and businesspersons encountering an isolating event as a result of militia or political violence is high,” it said. “The government of Libya does not yet have the ability to effectively respond to and manage the rising criminal and militia related violence, which could result in an isolating event.”

The Democratic memo said Nordstrom told committee investigators that he sent two cables to State Department headquarters in March and July 2012 requesting additional diplomatic security agents for Benghazi, but that he received no responses.

He stated that Charlene Lamb, the deputy assistant secretary for international programs, wanted to keep the number of U.S. security personnel in Benghazi artificially low and that Lamb believed the Benghazi facilities did not need any diplomatic security special agents because there was a residential safe haven to fall back to in an emergency.

Issa had a phone conversation Monday with Secretary of State Hillary Rodham Clinton about the committee’s investigation.

House Speaker John Boehner’s office on Tuesday hosted a State Department classified briefing for congressional staff of both parties. The meeting was a prelude to a briefing for the eight committee chairmen who raised questions about diplomatic security.

Kevin Smith, a spokesman for Boehner, R-Ohio, said, “House Republicans have long remained committed to responding decisively to acts of terrorism and are concerned the current policies are biased toward investigating the attack after the fact as a purely law enforcement response to a criminal act. There are clear deficiencies to this response, as evidenced by the inability to effectively seal-off the compound and by the reported inability to interview any individuals who may or may not be in custody.”

The FBI is investigating the attack, but Secretary of State Hillary Rodham Clinton also has named a State Department review panel to look into the security arrangements in Libya.