Shell says considering options on bid target Cove LONDON (Reuters) - Royal Dutch Shell (RDSa.L) said it was considering its options regarding Cove Energy (COVE.L), the explorer it is trying to buy, as it extended the deadline for shareholder acceptances in the face of a higher bid from a Thai firm. The takeover battle for Cove, which has a stake in huge gas finds off the coast of Mozambique, heated up on Wednesday after Shell's $1.8 billion offer was trumped by a $1.9 billion bid from Thailand's PTT Exploration and Production PTTE.BK. Shell said in a statement on Thursday that shareholders would have an extra three weeks to accept its 220 pence per share offer. Noting the competing bid from the Thai firm, the company added: Shell is currently considering its options and will make a further announcement if appropriate. Shares in Cove closed at 250 pence on Wednesday, higher than the 240 pence offer from the Thai firm, signaling that investors expect Shell to come back with a higher bid. East Africa is set to become one of the world's largest gas exporters, executives operating in the region believe, after a string of major discoveries across Mozambique and Tanzania. Shell, which unlike PTT has already been granted the approval of the Mozambique government, said to date it had acceptances from shareholders owning 4.83 percent of Cove's shares. Reporting by Sarah Young, Editing by Rosalba O'Brien