America Movil acquired more stock in KPN yesterday, upping the pressure on the Dutch operator group which is attempting to block the Mexican firm’s move to become a significant shareholder, fearing a hostile takeover.

Reuters reports that America Movil made four separate transactions yesterday to buy 6 million of KPN’s ordinary shares, increasing its stake to 7.3 percent. The firm had increased its stake to 5.01 percent two weeks ago when it unveiled its offer to eventually acquire 27.7 percent.

"All these transactions were entered into a price in cash of EUR7.8 euros per ordinary share," America Movil said in a statement. The price was in line with KPN’s EUR7.769 closing price yesterday, but below the EUR8 per share offer America Movil has on the table for KPN’s shareholders, which is valid until 27 June.

KPN has rejected that offer, saying it undervalues the company, and has also accused America Movil of not being willing to discuss options.

The Dutch group is now thought to be looking at the possibility of spinning off one or both of its mobile units in Belgium (BASE) and Germany (E-Plus) in an apparent bid to ward off the perceived hostile takeover threat.

KPN "felt threatened by the America Movil bid," analyst Valeria Romo at brokerage Monex, told Reuters. "They are somehow dismantling the business by selling units and that is perhaps giving KPN shareholders some uncertainty."

America Movil’s attempt to wrestle control of KPN represents its first major foray into Europe, though it has also built up a separate 4.1 percent stake in Telekom Austria.