ISTANBUL — Turkey’s government on Sunday issued a decree dismissing more than 18,000 state employees, a day before President Recep Tayyip Erdogan is set to begin a new five-year term bolstered by vastly enhanced powers.

The latest dismissals significantly expanded a government purge of state institutions that began after a failed coup two years ago. Before Sunday, at least 130,000 people had been fired based on what authorities said were links to terrorist groups. Human rights groups say the purge has also targeted the government’s political opponents and critics and has swept up others as well.

Nine thousand police officers and hundreds of soldiers and academics were dismissed from their jobs Sunday, according to the decree published in the state Gazette. Three newspapers and a television channel were shuttered, and 148 people who had previously been dismissed were reinstated.

The purge has been carried out under a two-year state of emergency that granted the government extraordinary powers and has come to define Turkey’s anxious, divided and frequently violent era since the coup attempt.

Erdogan is expected to lift the state of emergency as he begins his new term, bowing to a persistent opposition demand. But he will also gain significant powers as Turkey transitions from a parliamentary system to an ­“executive presidency” — a system the president’s critics say will entrench one-man rule.

Erdogan was reelected last month despite an unusually unified challenge by Turkey’s often fractured opposition. He will also command a majority in parliament because of an alliance between his ruling Justice and Development Party and another nationalist political party.

Changes to Turkey’s constitution that were narrowly approved by voters in a referendum last year eliminated the post of prime minister, enlarged the parliament and gave the president the authority to select the cabinet, control the budget and unilaterally issue decrees.

In arguing for the changes, Erdogan’s supporters had invoked Turkey’s history of tempestuous politics, current security threats and need to streamline an unwieldy bureaucracy.

“We will speed up the work of the state and make it effective by merging institutions that do similar work and eliminating institutions that have become dysfunctional,” Erdogan said on Saturday.

But the changes have also produced “a president with a heavy concentration of powers, without any effective checks or balances,” said Ergun Ozbudun, a Turkish constitutional law expert.

The most consequential impact, he said, is on the judiciary, because of changes in the way members of a senior judicial council are appointed. The president will, directly or indirectly, be able to appoint six of the council’s 13 members. The other seven will be appointed by a parliament expected to vote in Erdogan’s favor.

“If you control that body, it means you control the entire judiciary,” Ozbudun said.

“All 13 members are people the government has confidence in. We can no longer talk about an impartial judiciary,” he said.

While the president’s ability to issue decrees is an “important power,” such decrees could not limit political or civil rights, Ozbudun said. 

The lifting of emergency rule, if carried out, would be a positive step, he said, but it would not indicate the sort of policies Erdogan would pursue as he accumulates more power.

“Will they be more conciliatory, or more or less continue the same approach?” Ozbudun said. “That remains to be seen.”