WASHINGTON — The father of Christopher Stevens, the U.S. ambassador to Libya who was killed in the attack in Benghazi last month, said his son’s death shouldn’t be politicized in the presidential campaign.

“It would really be abhorrent to make this into a campaign issue,” Jan Stevens, 77, said in a telephone interview from his home in Loomis, Calif., as he prepares for a memorial service for his son this week.

Mitt Romney, the Republican nominee, has criticized President Obama for not providing adequate security in Libya, saying the administration left the country exposed to a deadly terrorist attack.

The ambassador’s father, a lawyer, said politicians should await the findings of a formal investigation before making accusations or judgments.

“The security matters are being adequately investigated,” Stevens said. “We don’t pretend to be experts in security. It has to be objectively examined. That’s where it belongs. It does not belong in the campaign arena.”

Stevens said he has been getting briefings from the State Department on the progress of the investigation.

The question of whether the embassy attack and the envoy’s death are being politicized came up on several Sunday morning television talk shows.

Obama campaign strategist David Axelrod told “Fox News Sunday” that Romney is “working hard to exploit this issue.”

Citing the interview with Stevens’ father, Axelrod said, “We ought to follow the ambassador’s family and allow this investigation to run and get to the bottom of it.”

Robert Gibbs, senior adviser to the Obama campaign, also cited the comments by Stevens’ father and said Romney is “playing politics with this issue.”

“We don’t need wing-tip cowboys,” Gibbs said on CNN’s “State of the Union” program. “We don’t need shoot-from-the-hip diplomacy, and when Mitt Romney first responded to what was going on in Libya, his own party called him out for insensitivity.”

Romney campaign adviser Ed Gillespie said on the Fox program that the country needs “honest and accurate answers.”

“What we have seen is a constantly shifting story from this administration,” Gillespie said.

“Why wasn’t security there? I believe folks deserve an explanation,” Ohio Sen. Rob Portman, a Romney supporter, told ABC’s “This Week.”

Stevens said that, while he was close to his son, “we weren’t that familiar with the day-to-day activities” he undertook in Libya. On the occasions when his son called home, Stevens said, he didn’t share many details about his work other than to say that “he was very optimistic about the results of the election and the new government.”

They last communicated by phone in August and by email days before his son’s death.

He said his son, a career diplomat who had worked for Republican and Democratic presidents, hadn’t expressed concerns to him about security or support from the administration.