Myanmar generals are back in charge, but for how long?

The military is back in power in Myanmar after a coup less than a decade after it launched a transition to democracy to end nearly half a century of direct army rule and international isolation.

The military pledged to stick to its 2008 constitution and return power via a free and fair election but set no clear timeframe and the junta detained elected leader Aung San Suu Kyi and purged her allies from the administration.

Economists say the coup could spook foreign investors and hit international development support, with the threat of a return of sanctions that made Myanmar among the world's poorest countries.

WHAT WAS ITS JUSTIFICATION?

The army said the administration had refused to act against "terrible fraud" in a Nov. 8 general election, which was won overwhelmingly by Suu Kyi's National League for Democracy (NLD) party. The military said it took power "to perform scrutiny of the voter lists" and the coup would protect democracy.

The military justified its coup within the parameters of the constitution, using a clause that allows for power to be transferred by the president to the armed forces chief in a state of emergency declared to address threats to the nation.

President Win Myint, a Suu Kyi ally, was among dozens of people detained early on Monday. Vice-president Myint Swe, a former general and member of the previous junta, then handed over power to the commander-in-chief, Senior General Min Aung Hlaing.

The electoral commission had repeatedly rejected the accusations of voter fraud.

WHAT OTHER FACTORS COULD THERE BE?

Observers with knowledge of Myanmar's secretive military suspect Min Aung Hlaing's personal ambitions and his limited options were a factor.

His mandatory retirement was imminent and it is highly unlikely an NLD-controlled parliament would have elected him president given the history of bad blood between the NLD and the army.

The military boss faces foreign accusations of war crimes against Rohingya Muslims, and is the subject of cases pending in international courts that could seek his arrest.

Myanmar experts also see the coup as a means to prevent any chance of an NLD-dominated legislature amending the constitution to reduce the military's powers - which include the right to 25% of the seats in parliament, an effective veto over the legislature.

Such constitutional change might have been made easier by the poor performance in November's election by the Union Solidarity and Development Party, the military's proxy, which won only 33 of 476 seats.

WILL THE MILITARY CEDE POWER?

The state of emergency will last for one year, as prescribed by the constitution, and the junta chief on Monday pledged to hold elections "upon completion of the tasks".

But after sacking Suu Kyi's cabinet it appointed a new group of ministers, none of whom were identified as "acting" or interim appointments.

Activists have already voiced strong doubts that the military will step down after only a year. The army ignored the NLD's win in a 1990 election for a constituent assembly and took nearly two decades to complete its promised transition to democracy.

WHAT DOES IT MEAN FOR THE ECONOMY?

The U.S. government has threatened renewed sanctions on Myanmar and the World Bank said the coup could hurt development prospects and gains in tackling poverty.

Political risk has been heightened by the takeover, with concern the junta will be preoccupied with establishing control and domestic security.

Any pro-democracy protests could be met with force. The nascent economy and jobs could be hit if foreign investors are concerned about stability or reputation risks. Vital infrastructure projects might be stalled or even be halted if private or public funding is affected.

Ratings agency Fitch called it a "substantial backtracking of progress" that will "weigh heavily on policymaking, social stability as well as international perceptions of the country".