UPDATE 1-United Financial raises offer for CNB Financial

* United Financial raises offer by about 3 pct

* New offer values CNB Financial at $23.4 mln

* New offer tops Berkshire Hills' revised bid

May 26 (Reuters) - United Financial Bancorp Inc (UBNK.O) raised its offer to buy CNB Financial Corp (CFNA.OB), topping a sweetened bid from Berkshire Hills Bancorp Inc (BHLB.O).

United Financial said it would now offer $10.25 for each CNB Financial share, valuing the deal at about $23.4 million.

On May 21, CNB rejected United Financial's earlier offer of $10 per share, saying Berkshire's all-stock deal will fluctuate with changes in Berkshire's stock price.

Berkshire Hills had revised its offer for CNB Financial, the parent company of Commonwealth National Bank, to $9.23 a share from $8.50 on May 21.

Worcester, Massachusetts-based CNB Financial has nearly $300 million in assets and operates six banking offices in the greater Worcester area, while United Financial had assets of $1.24 billion as of March 31.

Shares of United Financial closed at $12.97, while those of Berkshire Hills closed at $21.63 Tuesday on Nasdaq. (Reporting by Sweta Singh in Bangalore; Editing by Deepak Kannan)