PRAGUE, Czechoslovakia (AP) _ President Vaclav Havel relieved Defense Minister Miroslav Vacek of his duties on Wednesday and temporarily entrusted the defense portfolio to the prime minister, the state CTK news agency said.

Vacek, 55, a career soldier and longtime Communist Party member, had served as deputy defense minister under former Communist Premier Ladislav Adamec.

Wednesday's terse report gave no details or reasons for Havel's decision, but it quoted Parliament deputy Michael Kocab as saying the president realized it was ''high time'' for a civilian to head the Defense Ministry.

Havel's office declined comment.

Interim defense duties were transferred to Premier Marian Calfa.

Vacek later said on national television: ''I fully agree that it is suitable that I resign.''

But he added that ''the reservations some people had toward my person do not contribute to the peace and atmosphere necessary for carrying out complex changes, above all in the economic sphere.''

After thanking Havel for supporting him through his nearly 11-month tenure, Vacek urged Czechoslovaks to change their attitude toward the army.

''If you cannot love it, then as a start, at least abandon the grudge,'' he said.

Vacek played a major role in forming the coalition ''government of national understanding'' under Calfa after Czechoslovakia's peaceful revolution last November. It was the first government here in 41 years not dominated by Communists.

Vacek was appointed defense minister on Dec. 3, 1989, and left the Communist Party three months later.

''The president voiced his appreciation that army Gen. Miroslav Vacek did not permit the abuse of the army against the people by anyone,'' CTK said, referring to the November revolution.

But according to the agency, Kocab said Havel's decision was based on findings of a presidential commission set up on Sept. 10 to investigate military activities during the November revolution.

The commission is expected to submit its report Thursday.

Unconfirmed reports say the army was to have been used against the people who overthrew the Communist leadership through peaceful street demonstrations.

CTK said Havel also expressed his appreciation that Vacek ''loyally fulfilled all orders and initiated the process of fundamental restructuring of the Czechoslovak army.''

Some politicians blasted Vacek's appointment as defense chief in the new coalition government in June, seeing him as an unnecessary holdover of Communist influence.

A petition, signed by prominent student leaders, was circulated in Prague in recent weeks. It demanded Vacek's resignation and that of Calfa, also a former Communist party member.

CTK quoted the petition as saying, ''There is no way to ignore the halfhearted nature of events over the last 10 months. . . . We demand that all state bodies be cleansed of those who lack the moral and professional qualities needed for executing their functions.''

Finance Minister Vaclav Klaus meanwhile urged cooperation from trade unions on his sweeping economic reforms, which begin on Jan. 1, CTK reported.

Klaus, who plans a radical free-market reform of the ailing economy, warned workers and business against pursuing private interests at the cost of the general welfare of the community, the agency said.

Czechoslovkia's economy, one of Europe's most developed between the wars, has been devastated by four decades of Communist central planning.