* Says his election win was blow against Britain, U.S.
* Vows to pursue black empowerment economic policies
* Rival Tsvangirai to challenge disputed result in court
* Mugabe says past unity government was "retrogressive"
By MacDonald Dzirutwe
HARARE, Aug 7 (Reuters) - Zimbabwean President Robert Mugabe on Wednesday defiantly rejected Western criticism of his disputed re-election and vowed to press ahead with nationalist economic policies transferring majority stakes in foreign-owned firms to blacks.
In his first public comments since he was declared winner of a July 31 election that his main rival Morgan Tsvangirai rejects as fraudulent, Mugabe, Africa's oldest leader at 89, said his ZANU-PF party's victory had "dealt the enemy a blow".
He identified this enemy as "the British and their allies" whom he said had backed Tsvangirai's Movement for Democratic Change (MDC) in the southern African state. Tsvangirai has said his MDC will challenge the election outcome in court, alleging massive vote-rigging and intimidation by ZANU-PF.
Addressing ZANU-PF's politburo in Harare, the veteran Zimbabwean president, who has ruled the former Rhodesia since independence in 1980, said Western governments had pledged to consider lifting sanctions if the elections were free and fair.
"But now they, even as the whole of Africa is sending us messages of congratulations to say 'well done', they say the elections were not free. And where are they talking? London and Washington and Ottawa," he added.
While election observers from the African Union and the Southern African Development Community (SADC) broadly approved the July 31 presidential and parliamentary elections, the vote has met serious questioning from the West.
The United States, which maintains sanctions against Mugabe, has said it does not believe his re-election was credible. The European Union, which has been looking at easing sanctions, has also expressed concerns over alleged serious flaws in the vote.
Mugabe, flanked by his deputy Joice Mujuru and party national chairman Simon Khaya Moyo at the politburo meeting, indicated his critics should not expect any let-up in economic nationalism policies that have also earned Western disapproval.
"All the time we must take into account our policy of indigenisation and empowerment," he said, referring to policies aimed at increasing black ownership of the economy that have already targeted foreign-owned mining companies and banks.
"Our task is to look ahead. What we say we shall do, we will do," added Mugabe, looking dapper in a grey suit and a light blue shirt and matching dotted tie.
The Zimbabwe stock exchange's main Industrial Index shed one percent on Wednesday, following a 1.7 percent fall on Tuesday and an 11 percent drop on Monday, the first trading day after Mugabe's re-election was formerly announced by the country's election commission at the weekend.
COURT CHALLENGE BY FRIDAY
Investors fear that ZANU-PF's boosted majority - it now controls more than two-thirds of the seats in the Zimbabwean parliament - could embolden it to pursue even more radical economic nationalism of the kind that led to the violent seizure of white-owned farms after 2000.
Last week's election, criticised as "seriously compromised" by independent domestic observers in Zimbabwe, ended a fractious unity government between Mugabe's party and Tsvangirai's MDC that was brokered by SADC after violence marred a 2008 vote.
Many had credited this unity government with achieving a measure of economic revival after a decade of recesssion.
But Mugabe presented a different view, calling "the immediate past ... retrogressive because of the inclusive government". "We must now raise the standard of living of our people," he added.
Tsvangirai, who has vowed his MDC will not participate in any government formed by Mugabe following this election, is expected to present a legal challenge to the results by Friday.
The constitution says the courts must rule on the case within 14 days. Mugabe will be sworn in only after the courts give the all-clear to any legal challenges, this being the most likely expected outcome given ZANU-PF's dominance of the judiciary and the institutions of state in Zimbabwe.
Mugabe, re-elected for a fresh five-year term after 33 years in power, showed no signs of ill health. He has been the subject of health rumours because of numerous visits to Singapore in the last three years for medical checks.
He travelled to Singapore in June for another check up just weeks before the July 31 elections. (Reporting by MacDonald Dzirutwe; Editing by Pascal Fletcher and Michael Roddy)