VIENNA, Austria (AP) _ The Bulgarian National Assembly elected Georgi Atanassov to replace Grisha Filipov as premier Friday in a major government shuffle, the state-run news agency, BTA, reported.

The former premier retained his membership in the Bulgarian Communist Party's policy-making Politburo and his post of secretary of the party's Central Committee.

Atanassov is a full member of the Politburo.

The changes appeared to indicate the government was tightening its top apparatus in advance of the Bulgarian Communist Party Congress, scheduled to begin April 2 to set national policies for the next five years.

There have been a series of top-echelon shuffles linked to a new economic policy, putting emphasis on greater efficiency and giving state enterprises a measure of independence.

Six ministries were closed down, among them the Ministry of Mechanical Engineering, of Power Engineering and Metallurgy. Their respective ministers lost their jobs.

Ilcho Dimitrov took over from Alexander Fol as minister of national education and Alexei Ivanov was named minister of farming and woods, while Georgi Georgiev was appointed chairman of the Committee for State and People's Control, BTA reported. The latter two were apparently new posts.

In the last top-level shuffle, the Bulgarian leadership on Jan. 27 announced major changes affecting several ministries and other agencies in an apparent effort to streamline and improve economic and technological management.