Ukrainian President Leonid Kuchma has unveiled a number of proposals to give more of his powers to parliament, just days before a new wave of opposition protests.
President Kuchma warned he would fight any attempts to stall his reform
In a television address, President Kuchma said the constitutional reform was aimed at resolving destructive confrontation between the executive and legislative branches.
He urged Ukrainians to back his proposals during a popular debate and accused the opposition of stalling his reform drive.
The president's proposals come as opposition parties are gearing up for fresh protest over the weekend to demand Mr Kuchma's resignation.
The opposition accuses the president of harassing his opponents and opposition media, and also of being involved into the murder three years ago of a prominent journalist, Georgiy Gongadze.
President Kuchma denies all the allegations.
Mr Kuchma said his reform package was aimed at creating a "parliamentary-presidential system... that conforms with the democracies in Europe".
Under his plan, the president would lose the authority to appoint the prime minister, which in future would be decided in parliament.
Last year's protests nearly toppled President Kuchma
The president would be limited to appointing only four cabinet ministers - internal affairs, defence, emergency situations and foreign affairs.
Mr Kuchma also proposed to transform the parliament into a bicameral body, which he said would improve the representation of Ukraine' regions.
The president also said Ukraine needed to change its election law and elect parliament on party lists.
Currently half of the parliament is elected on party lists, while the other seats are contested in single constituencies.
He said the reform package would be submitted to parliament on Thursday, and warned that he would fight any attempts by the opposition to derail the reform.
"I am not going to put at risk the future of political reform and the future of the country. Let people discuss the main issues of the reform... and parliament should approve it," he said.
'Test of strength'
Mr Kuchma first suggested the transfer of some of his powers in August last year, just days before nationwide opposition protests that nearly toppled him.
Some experts say the timing of the new initiative is an attempt by the president to strike a pre-emptive blow against opposition protests planned for the weekend.
The opposition accuses Mr Kuchma of worsening living standards and corruption and also of being involved in the murder of Georgiy Gongadze.
President Kuchma has also been under pressure from the United States to explain allegations that Ukraine broke UN sanctions on Iraq by supplying sophisticated radar equipment.
But Mr Kuchma has managed to weather the storm, and some of the analysts said his new proposals were a test to see if he can get enough support in parliament to change the constitution and stand for a third term.
Mr Kuchma was re-elected in November 1999 to a second five-year term and has since seen his poll ratings plunge.