FACTBOX: What next in Zimbabwe's struggle for power?

(Reuters) - Zimbabwe's political situation has evolved rapidly since March 29 elections in which President Robert Mugabe lost control of parliament for the first time in his 28-year rule.

Below are answers to some key questions as tension rises between Mugabe's ruling ZANU-PF party and the opposition Movement for Democratic Change (MDC).

WHAT RESULTS ARE KNOWN?

Official results give the MDC 99 seats in parliament, a breakaway opposition faction 10 and ZANU-PF 97. One seat went to an independent.

No presidential results have so far been released.

Senate results show contested seats split 30-30 between the combined opposition and the ruling party. Control of the 93-seat Senate will depend on who becomes president, with powers to directly appoint 15 members and strongly influence who gets other positions.

The MDC said its leader Morgan Tsvangirai won the presidential poll outright. ZANU-PF projections show that although he won, he fell short of the absolute majority needed for first-round victory.

WHY ARE DELAYS SIGNIFICANT?

In past polls, results emerged quickly. This time there is no presidential outcome after nine days. According to electoral rules, a runoff between Tsvangirai and Mugabe should be held within three weeks of the results announcement. The longer the delay, the more time Mugabe has to organize his fightback.

WHAT IS MUGABE'S STRATEGY?

A few days ago, Mugabe looked badly wounded by the parliamentary defeat and there was speculation he would step down. But strong backing by security chiefs appears to have strengthened the government's resolve to counter-attack.

ZANU-PF's emerging strategy appears to be to:

- Challenge some parliamentary results through the courts and demand a recount in the presidential vote because of alleged irregularities.

- Delay the presidential result and any runoff. ZANU-PF has asked electoral officials to defer presidential results pending a recount. There are suggestions Mugabe will use presidential powers to extend the interval before a runoff to 90 days.

- Deploy pro-government militias including youth brigades and the feared independence war veterans to intimidate MDC supporters before a new vote. The veterans, awarded big pensions and formerly white-owned farms under Mugabe's controversial land reform program, have already emerged to strongly back him.

WHAT IS MDC STRATEGY?