Qatar on Thursday lodged a "final offer" to buy the owner of London's landmark Canary Wharf office quarter for £2.6 billion ($4.1 billion, 3.3 billion euros).
Sovereign wealth fund Qatar Investment Authority and US group Brookfield Property Partners said in a statement they have increased their bid for Songbird, a property firm which controls 69 percent of Canary Wharf Group.
The cash bid, pitched at 350 pence per share, compared with the previous 295-pence-per-share or £2.2-billion offer that was rejected last month by Songbird. The group has yet to respond to the improved bid.
"QIA and Brookfield... believe the Songbird final offer price to be full and fair, based on their view of the fundamental value of Songbird's existing assets," the pair said in a statement.
They added that they "wish to avoid a protracted debate on value and so minimise the uncertainty for the management of CWG".
The QIA, which owns Harrods department store and the Shard skyscraper in London, already has a 28.6-percent stake in Songbird.
Brookfield meanwhile owns 22 percent of Canary Wharf Group.
The former Docklands area of London where Canary Wharf is located was re-developed in the 1980s and continues to be a magnet for huge building projects -- after falling into disrepair when the city's status as a trading hub declined.
QIA also owns significant stakes in British supermarket chain Sainsbury's and the London Stock Exchange, as well as half of the Olympic Village apartments in the capital's Stratford district.