Some executives within Citigroup are pushing for the U.S. banking giant to make a bid for ABN AMRO, which is in discussions about a possible merger with Barclays, a newspaper reported Friday.

Citigroup (Charts) is studying whether to make a bid for ABN AMRO (Charts), the Netherlands' biggest bank, and could make a hostile bid, the Wall Street Journal said, citing unnamed people familiar with the matter.

Spokespeople for both banks declined to comment.

Barclays (Charts) has clinched an exclusive agreement to negotiate with ABN AMRO and has drawn up a broad merger outline for a combined bank worth more than $166 billion that would be listed in London, headquartered in Amsterdam and have its two top jobs split.

Citigroup, HSBC (Charts), Royal Bank of Scotland and Santander (Charts) have been cited as analysts as potential other bidders for ABN AMRO, which entered into talks with Barclays after hedge TCI called on the Dutch bank last month to break up or sell itself to boost returns to shareholders.

ABN AMRO shares were flat in Amsterdam, at €31.72, but up more than 14 percent in the last month. The DJ Stoxx Banking Index was down 2.8 percent at in premarket trade.

Barclays was down 0.3 percent at 737 pence on the London Stock Exchange in premarket trade. Citigroup closed 0.4 percent lower at $51.84 on the New York Stock Exchange.

Analysts have warned that if and when Barclays makes an offer for ABN AMRO, expected within the next one or two weeks, a counter-bidder could come in with a more lucrative offer.