Democratic Progressive Party leader Peter Mutharika was declared the winner of Malawi's disputed presidential election on Friday after defeating President Joyce Banda.
Mutharika, the brother of former president Bingu wa Mutharika, took 36.4 percent of the votes cast against Banda's 20.2 percent, the electoral commission said.
The results were announced minutes after the high court refused a last-ditch attempt to block their release and allow time for a recount.
Electoral commission chief Maxon Mbendera declared Mutharika "president-elect" after last week's vote, which Banda said was marred by "serious irregularities" and "null and void".
The results showed that Banda was beaten into third place by Lazarus Chakwera of the Malawi Congress Party (MCP), who garnered 27.8 percent of the vote.
Party spokeswoman Jessie Kabwila told AFP the MCP, which had made the bid for a recount, would challenge the results in court.
"We are disappointed because this is not a credible election. We will fight through legal means...we are not taking this lying down."
Mutharika is set to take the reins of the impoverished southern African country under the shadow of a treason charge.
The 74-year-old brother of former president Bingu wa Mutharika is accused of attempting to conceal his brother's death in office two years ago in an attempt to prevent Banda -- then vice-president -- from assuming power.
Banda prevailed and took office as decreed by the constitution, booting the former foreign minister out of the administration.
Mutharika, a law professor and former cabinet minister, faces additional counts of inciting a mutiny and conspiracy to commit a felony, along with other officials.
The trial is still pending, but analysts say it is likely the case will be set aside as Malawi's presidents enjoy immunity from prosecution as long as they are in office.
There is speculation that once Mutharika is in power he could turn the tables on Banda and have her charged with corruption over a $30 million graft scandal dubbed "Cashgate".
Banda has claimed the credit for uncovering the fraud, which saw aid money syphoned into top government officials' pockets. But critics, including Mutharika, say the funds went into her party's election war-chest.
"Banda did everything in her power to prevent Mutharika from becoming president... and then bringing charges against her," said Clive Gabay of the Queen Mary University of London.
The election in the tiny southern African nation was dogged by controversy from the start, with some polling stations opening 10 hours late and some voting stations recording more votes than there were registered voters.
Anyone with complaints has seven days to lodge petitions with the courts.
Riot police patrolled key areas of the commercial capital Blantyre as the results were announced after earlier demonstrations turned violent.
One person was killed when police fired teargas and rubber bullets at protesters demanding a recount in the southeastern town of Mangochi.
A teenager was "killed by a teargas canister, which exploded in his hands as he was trying to throw it back at us," Mangochi police officer Elijah Kachikuwo told AFP.
The election imbroglio is unlikely to help Malawi's dire economic problems.
After taking office Banda oversaw the devaluation of the kwacha currency by 50 percent, the easing of foreign exchange restrictions, along with the raising of fuel prices and cutting of subsidies.
That helped restore an IMF credit line, but the country remains overly dependent on agriculture and foreign aid to survive.
Mutharika has said he will not pursue trickle-down economics, but will implement "bottom-up economics aimed at getting the poor out of poverty into prosperity".
Some 7.5 million people were eligible to choose a president, lawmakers and local government councillors in the fifth democratic polls since the end of decades of one-party rule in 1994.