YANGON (Reuters) - Myanmar’s army on Tuesday rejected allegations of human rights abuses during its crackdown on Rohingya Muslim last year, made by the United Nations in a report on the offensive that forced some 75,000 Rohingya to flee to neighboring Bangladesh.

The crackdown, in response to attacks by Rohingya insurgents on border guard posts on Oct. 9, poses the biggest challenge yet to Myanmar’s leader and Nobel laureate Aung San Suu Kyi, who took power more than a year ago.

Myanmar’s security forces committed mass killings and gang rapes of Rohingya in a campaign that “very likely” amounted to crimes against humanity and possibly ethnic cleansing, the Office of the High Commissioner for Human Rights (OHCHR) said in a report published in February.

“Out of 18 accusations included in OHCHR’s report, 12 were found to be incorrect, with the remaining six found to be false and fabricated, based on lies and invented statements,” the state-run Global New Light of Myanmar newspaper said in an article on Tuesday that summed up the internal military inquiry.

It said military investigators, among others, interviewed nearly 3,000 villagers from 29 villages and “wrote down” testimony from 408 villagers, 184 military officers and troops.Three low-ranking soldiers were jailed for minor offences, such as stealing a motorbike or beating up villagers in one incident, it added.

Apart from the completed military inquiry, a national panel set up by Suu Kyi in December and chaired by vice president Myint Swe, a former head of military intelligence, is also looking into the allegations.

Besides the latter investigation, the ministry of home affairs, which is controlled by the army, is also carrying out an inquiry. Separately, the U.N. has ordered a fact-finding mission to examine allegations of human rights abuses.