Malaysia's Prime Minister plans a nationally televised address on Wednesday where he is expected to dissolve Parliament for general elections to be held within two months.
The polls will be fiercely contested between Prime Minister Najib Razak's long-ruling National Front coalition and opposition leader Anwar Ibrahim's three-party alliance.
His office says Najib will address the nation at 11.30am (0330 GMT). The announcement did not say what he would discuss, but national speeches with so little advance notice are extremely rare.
The National Front's current five-year mandate ends April 30.
Najib was meeting with his Cabinet before the speech. He also met earlier on Wednesday with the country's constitutional monarch and could have sought royal consent to dissolve Parliament.
Voting must be held within two months after Parliament is dissolved.
At stake are 222 seats in Parliament and control of 12 Malaysian states. The National Front won 2008 elections with less than a two-thirds parliamentary majority, its poorest results in more than five decades of uninterrupted rule since independence from Britain in 1957.
Najib was marking exactly four years as Prime Minister on Wednesday. He succeeded Abdullah Ahmad Badawi, who was pressured to step down after being blamed for weak leadership that contributed to the National Front's electoral setback.
Anwar's opposition alliance wrested control of several states in 2008 by pledging to curb long-entrenched problems including corruption and racial discrimination.
Najib has intensified efforts to win back support over the past year with measures such as channeling more funds to the poor and abolishing security laws that were widely considered repressive.
Most analysts believe Najib's coalition will still have the upper hand because of its support in predominantly rural constituencies that hold the key to a large number of Parliament's seats.