NAIROBI (Reuters) - A former lawmaker filed a petition at Kenya’s Supreme Court on Monday challenging President Uhuru Kenyatta’s victory in last month’s presidential election in a last minute move that opens the door to legal scrutiny of the vote.

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Harun Mwau filed the petition hours before a Monday deadline set by the constitution expired. Earlier in the day, a coalition of civil society groups said they were being targeted by the government in an effort to head off potential legal cases.

The Supreme Court has until Nov. 14 to rule on election petitions. If it upholds the result, Kenyatta will be sworn in on Nov. 28.

Kenyatta came to power in 2013 and won a second and final term in August, defeating opposition leader Raila Odinga by 1.4 million votes. The Supreme Court nullified the vote citing procedural irregularities and ordered a second election.

Odinga did not contest the repeat vote on Oct. 26 saying it would be unfair because the election commission had failed to implement reforms. Kenyatta won with 98 percent of the vote, though opposition supporters staged a boycott and prevented polls from opening in the west of the country.

Kenya is a regional hub for trade, diplomacy and security and its prolonged election season has disrupted its economy.

Rights groups said on Monday the government was trying to prevent them from lodging cases challenging the Oct. 26 result. The government’s NGO Board, which monitors civil society organizations, summoned three groups for an audit on Monday, they said.

“It is not a coincidence that the NGO Board has decided to come after these organizations. All three have been instrumental in calling for free, fair, and credible elections,” said a statement from Kura Yangu Sauti Yangu, a coalition of civil society groups that monitored the election.

The name means My Vote My Voice in Kiswahili.

The three organizations, Katiba Institute, Muslims for Human Rights and Inuka Trust, belong to the coalition. The head of Muslims for Human Rights said he had planned to file a court challenge.

Kura Yangu Sauti Yangu deployed 2,000 monitors for last month’s vote and said it found multiple cases where results from polling stations differed from results on the forms posted on the election portal.

“They are trying to attack everywhere to see who is preparing to go to court so that they stop it,” Tom Oketch, secretary general for the Coalition for Constitutional Implementation, told a news conference.

Calls to Fazul Mohamed, the NGO Board’s executive director, went unanswered. Mwenda Njoka, a spokesman for the interior ministry, under which the board falls, said only Mohamed could comment.

In a separate case, another organization filed a case against the opposition, seeking to hold them liable for losses incurred because of their demonstrations.