Deals of the day -- mergers and acquisitions

May 25 (Reuters) - The following bids, mergers, acquisitions and disposals involving European, U.S. and Asian companies were reported by 0400 GMT on Monday.

(For Reuters columns on deals, click on [DEALTALK/])

** Asia's largest oil and gas producer PetroChina (0857.HK) is buying Keppel Corp's (KPLM.SI) 45.5 percent stake in Singapore Petroleum Company (SPC) for S$1.47 billion ($1.02 billion) and plans to make a general offer to buy the rest of the firm.

To read more, click on [nSHA475591]

** National Australia Bank Ltd (NAB.AX) and AMP Ltd (AMP.AX) are among the parties to have submitted indicative bids for the Australian unit of British insurer Aviva Plc (AV.L), a source with direct knowledge of the matter told Reuters. [nSYU006580]

** China's Weichai Holdings Group, Shandong Construction Machinery Group Co and Shandong Auto Industrial Group will merge to form an auto parts maker targeting more than 100 billion yuan ($14.6 billion) in sales by 2012, their listed units said. [nSHA141255]

** Magna International MGa.TO and Fiat (FIA.MI) have improved their offers for General Motors (GM.N) unit Opel ahead of a crucial week in which the German government is expected to decide which bid to back. [nLO709586]

** Harbinger Capital, one of Asarco LLC's largest bondholders, is seeking to offer its own $500 million reorganization plan for the bankrupt U.S. copper miner, battling India's Sterlite Industries (STRL.BO) and Asarco's parent Grupo Mexico (GMEXICOB.MX) for control of the company. [nN22374245]

** Stricken German luxury fashion house Escada ESCG.DE has agreed to sell its Primera unit with a hefty write-down, pushing its first-half earnings deeper into the red, it said. [nLM449622] (Compiled by Tina Kwan in Singapore)