A $4.5B merger of data center operators has clouded as one of the firms, UK-based Telecity, said today it is has been approached by US-based Equinix in a $3.5B takeover bid.

The news left Telecity's previously announced merger partner, Interxion Holding of Amsterdam, which is publicly traded in New York, reaffirming its support of the $4.5B Telecity deal but warning that exclusivity obligations have been dropped as its partner is courted by another firm.

Brunswick Group is advising Telecity on the PR front. The company said its directors have a fiduciary duty to listen to third party offers and that it will allow Equinix a short period of due diligence.

Joele Frank, Wilkinson Brimmer Katcher counsels Interxion Holding of The Netherlands.

And London's Tulchan Communications, led by former Brunswick partner Andrew Grant, is advising Equinix. Ian Bain is senior director of PR for the Redwood, Calif.-based company.

Reuters called US-based Equinix's entry into the fray a bid to "gatecrash" the Telecity-Interxion deal, announced in February.

The Europe-centered merger dance comes as the continent is scrambling to meet growing demand for digital, data and cloud services.