A high State Department official testified yesterday that Rep. Charles O. Diggs Jr. (D-Mich.) reported an agreement bribe attempt of "five figures' by an African head of state in 1972 [WORD ILLEGIBLE] .

Diggs according to the testimony of David D. Newsman. Undersecretary of State for Political Affairs, "was offered a [WORD ILLEGIBLE] to further the country's cause in Congress." Diggs turned over a letter carrying the offer to him. Newsman said, but the letter has since been misplaced by the State Department and could not be located.

"Newsman was called yesterday by Diggs defensive lawyers as they opened the case in the Michigan congress- [WORD ILLEGIBLE] on charges of mail fraud and illegally diverting congressional pay for his staff to his own use. Newsman described Diggs as "a man of integrity and honesty," citing the reporting of the attempted bribe as an example.

Newsman was not asked and did not say who made the offer or what country was invited. He declined to tell reporters after his testimony.

Asset in cross-examination by prosecutor John Katelly whether Diggs had any further contacts with the African head of state on the matter, Newsman said that "to the best of my knowledge" Diggs had not. Newson said in response to another question that he did not know whether any such contacts had been made.

The prosecution concluded its presentation of evidence against Diggs by midafternoon, but only after one of its witnesses testified that regulations of the House of Representatives from 1970 to 1976 were vague about what constituted "compensation" of a congressional staff employe.

John Lawler, head of the finances office of the clerk of the House, said House regulations during that period were "silent" on what "official duties" for a congressional employ might include.

Diggs is accused of inflating the pay of some congressional employes and then using the extra money to pay personal and congressional bills. The defense has argued that House regulations were vague concerning the practice as far as paying congressional bills were involved, and that a later change in House regulations in 1977 legalized what Diggs did.

At the end of the prosecution's case, assistant defense attorney Bernard Carl argued that U.S. District Judge Oliver Gasch should dismiss all charges against Diggs for lack of evidence and on constitutional grounds, Gasch denied the motion.

It also was disclosed yesterday that Gasch had denied an attempt by defense lawyers to present testimony on Diggs' behalf by former president Gerald R. Ford, who served in Congress with Diggs. Gasch declined, after the government objected, to waive a requirement that the defense give 10 days' notice before presenting Ford's testimony, which would have been contained on video tape.