It does not look as if Mr. Mugabe, an 84-year-old liberation hero who has ruled Zimbabwe for 28 years, will leave office without a fight. After early election results from the March 29 vote indicated he was losing to the opposition leader, Morgan Tsvangirai, the election commission put the brakes on announcing results. The presidential results still have not been released, and a recount begun Saturday in 23 Parliament races is now threatening to drag things out further  the opposition has deemed it “illegal.”

Image More than 1,000 people cross the border from Zimbabwe into South Africa every day. Credit... Mariella Furrer for The New York Times

If there is a runoff between Mr. Mugabe and Mr. Tsvangirai, many fear it could get even bloodier. Human Rights Watch issued a report on Saturday saying members of Mr. Mugabe’s party were running “torture camps” where they took opposition supporters for nightly beatings.

On Sunday, the leading opposition party, the Movement for Democratic Change, said more than 400 supporters had been arrested, 500 attacked, 10 killed and 3,000 families displaced. The party released a detailed, day-by-day chronicle of violence that listed huts being burned, people getting cracked in the head with bottles and farms being invaded. The party blamed Mugabe supporters and sometimes government soldiers.

The government has denied any wrongdoing and accused opposition leaders of treason. Mr. Tsvangirai has said it is too dangerous for him to stay in Zimbabwe and has been spending time in South Africa.

The border between South Africa and Zimbabwe stretches about 150 miles, and it is headache-hot out here. “Beware of crocodile” signs shimmer in the sun, the grass is yellow and crisp, and at night, the trees churn with clouds of heat-crazed insects.

For the people who make it through, there is a pipeline of sympathy waiting on the other side. Fellow Zimbabweans living in South Africa  often perfect strangers  have taken in border jumpers, giving them a safe house and a warm cup of porridge, and helping them along their way to Messina, about 10 miles south, and then onward to the bigger cities of Johannesburg and Cape Town.