(Adds share price, views of why results release delayed)
By Stephen Eisenhammer and Alberto Alerigi
RIO DE JANEIRO, Feb 13 (Reuters) - The board of Brazil's Usiminas on Friday blocked the release of fourth-quarter results, as the steelmaker reels from the departure of its previous chief executive over bookkeeping concerns that sparked a battle between controlling shareholders.
Usinas Siderurgicas de Minas Gerais SA, as the company is formally known, was supposed to release financial results on Friday morning.
The company informed investors minutes before markets opened of the decision of the board not to approve management's report of the quarterly results.
The board also rejected management's proposed divided payment for 2015, the statement said, without giving reasons for either move.
Following Usiminas' announcement, the company's preferred shares fell 4 percent in early trade, but were up 0.6 percent in early afternoon trading in São Paulo.
Usiminas - which is Brazil's largest flat steelmaker - did not set a new date for a release for the quarterly report. Flat steel is used extensively in the auto and appliance industries.
One source familiar with the matter told Reuters the board unanimously voted against publishing the results due to accounting questions over some items. However, a second source said the board vote had more to do with the power struggle at the steelmaker than accounting, adding that auditor Ernst & Young had signed off on the numbers.
"There were questionable management actions" under former CEO Julián Eguren, the first source said, explaining that more than 100 large contracts had been signed without the mandatory approval by the board needed for those cases.
Both sources expect financial results to be unveiled before a March 31 deadline set by Brazil securities industry watchdog.
The delay follows the high-profile failure of state-run oil company Petroleo Brasileiro SA to publish audited quarterly results due to a deepening corruption scandal. There is no indication that issues at Usiminas would be similar.
Eguren, who during his two-year stint brought Usiminas back to profitability by slashing costs and easing bottlenecks, was forced out last September for alleged inappropriate receipts of money.
His dismissal prompted a rift between controlling shareholders Ternium SA and Nippon Steel & Sumitomo Metal Corp, with Eguren denying wrongdoing and Ternium demanding his reinstatement. Nippon refused.
However, if the vote to delay the publishing of results was unanimous as one of the sources said, it suggests the spat may be moving into a new stage with both parties admitting that errors were made by previous management.
Reporting by Stephen Eisenhammer; Editing by Chizu Nomiyama and W Simon