The acting president of Bangladesh vowed today to "foil any conspiracy" against a trend toward democracy begun by assassinated president Ziaur Rahman.

In an emotional news conference during which he sometimes appeared on the verge of tears, Abdus Sattar, vice president under general Zia, as Ziaur was known here, also repeated a pledge to hold a presidential election within 180 days as called for in Bangladesh's constitution. But he ruled out his own candidacy, citing poor health.

Although Sattar expressed determination to continue "the democratic process" in Bangladesh following an abortive rebellion last weekend that took the president's life, a certain apprehension about the country's future sometimes showed through. His remarks also failed to clear up some of the mysteries still surrounding the rebellion and its aftermath, particularly the death of rebel leader Maj. Gen. Abul Manzur.

Asked about an apparent discrepancy in official versions as to whether soldiers or civilians killed Manzur, the 75-year-old Sattar said this was "being investigated." He indicated that no one has been arrested for the slaying.

"We wish he [Manzur] was alive," Sattar said. "We would have tried him according to the law." He dismissed the suggestion that Manzur was killed in a cover-up by other military men involved in the two-day rebellion in the southern port city of Chittagong.

Asked about the possibility of new military intervention before the elections, for which no date has yet been set, Sattar said, "I hope this will not happen again." A spokesman for Sattar said that because of monson rains, the polling probably would take place between mid-September and the end of November.

Sattar said that Bangladesh was "determined today to preserve independence and sovereignty and foil any conspiracy to disturb the democratic process in the country."

Wearing a gray suit with a black armband, the ailing interim president repeatedly came back to Zia's death, lauding the general's accomplishments and recalling his last hours in Chitagong. His voice choking with emotion, Sattar said, "He was like my son. I loved him too much. I loved him because he was trying to build a small country in a better way."