South Sudan’s president has issued a Christmas decree creating 28 new states in a bid that may undermine a peace deal in the African country .

The 28 states make the previous 10 regions "defunct," state radio announced late Thursday.

Seven of the 10 previous governors have been reappointed, according to media.

Critics say President Salva Kiir's political move constitutes a threat to a peace deal signed in August to end the country's two-year civil war.

The peace deal rests on a power-sharing scheme in the original 10 states between Kiir and rebel leader Riek Machar, who also served as the former vice president, as well as other political groups.

Meanwhile, the rebel leadership is consulting about its reaction to the president's action, Machar's spokesman James Gatdet Dak said Friday.

The president's decree is unconstitutional because it violates the signed peace agreement and because the parliament, not the president, has the power to change state borders, said Lam Akol, the head of South Sudan's official opposition, the SPLM-Democratic Change party.

The new states divide South Sudan along tribal lines and the opposition party will not recognize the new states, Akol stated.

Kiir first announced that he intended to create the 28 states in October.

The president's action is "unfortunate" because it presents a "key challenge" to implementing the peace agreement, said the activist group Community Empowerment for Progress Organization, based in the capital, Juba, in a statement on Friday.

South Sudan's civil war began in December 2013. Tens of thousands have been killed in the fighting, which has forced more than two million from their homes.

South Sudan gained independence from Sudan on July 9, 2011.