Najib Abdul Razak was sworn in for a second term as Malaysia's prime minister on Monday, a day after the ruling coalition struggled in a general election that was marred by allegations of irregularities.
Najib, 59, took the oath of office for another five-year term in a ceremony attended by King Tuanku Abdul Halim Mu'adzam Shah at the National Palace.
The ruling 13-party National Front coalition, popularly known as BN, secured 133 of the 222 parliamentary seats in Sunday's poll, while the opposition led by Anwar Ibrahim seized 89 seats, up from 82 in the 2008 general election.
At state-level elections, BN won back the northern Kedah and Perak states, which it had lost to the opposition in the 2008 elections.
The ruling coalition now controls 10 of Malaysia's 13 states. The states of Penang, Kelantan and Selangor remain under opposition control.
While Najib called on all parties to accept the outcome of the elections, Anwar refused to concede defeat, claiming massive vote rigging.
"The fact that (opposition alliance) Pakatan Rakyat won the popular votes by a large margin, 50.3 percent compared to BN's 46.8 percent, confirms the mandate given to us and highlights that electoral frauds won the 13th general election for Dato Seri Najib Abdul Razak," Anwar said in a statement.
"Our conscience cannot allow us to accept election results conjured through frauds and cheating," the statement said.
Pakatan Rakyat, or the People's Alliance, refers to a three-party coalition comprising Anwar's People's Justice Party, the predominantly Chinese Democratic Action Party and the fundamentalist Pan Islamic Party.
Anwar, 65, a former deputy prime minister, had earlier said he would retire from politics to teach if he failed to defeat BN. Now he said he would devote his time and energy to ensure that a newly constituted and independent Election Commission will be in place as soon as possible to "rectify the electoral frauds."
The nongovernmental election watchdog, BERSIH, or the Coalition for Clean and Fair Elections, has described Sunday's poll as "the dirtiest ever" and said it will set up a panel to investigate claims of fraud.
BERSIH, which has been instrumental in raising public activism toward the electoral process, also said it is withholding recognition of Najib's government and called for a boycott of the mainstream media, owned by entities linked to the ruling parties, accusing them of aiding and abetting the uneven playing field.
Najib denied the fraud allegation and said the electoral process was "true, fair and transparent."
"It's been a long and hard-fought election. Now it's time to move toward national reconciliation," he said, while urging Malaysians to accept the outcome of the general election and "show the world we are a mature democracy."
While the BN retained a majority in parliament, Sunday's election result was the worst in its history. The coalition failed to wrest back its traditional two-thirds hold in the parliament.
Najib blamed the poor performance on the abandonment of the ruling coalition by the Chinese community.
The minority ethnic Chinese, disgruntled with the government's pro-Malay policies and rampant corruption, remained solidly with the opposition, continuing a trend that was first seen in 2008.
Ethnic Chinese make up nearly one-third of Malaysia's population of 29 million.
BN entered into the election counting on the Malays, who make up nearly 60 percent of the population, to deliver the vote.
The Malays especially in the rural areas have long relied on government handouts and were the beneficiaries of the affirmative action that accord them special privileges from bigger quota in public universities to special discounts in housing prices and easier access to government contracts.
The opposition has leveled criticism that the government's pro-Malay policy has been abused and government contracts are now being doled out to enrich cronies to buy their support and loyalty.
Najib's own party, the United Malays National Organization, is expected to hold a leadership election by the end of this year. Najib's failure to lift BN to a better poll result could jeopardize his position as UMNO president and hence the country's prime minister.