The merger of Mitsubishi Tokyo Financial Group Inc. and UFJ Holdings Inc. in October has stumbled and the firms intend to postpone integrating their core banking units for another few months, sources said Thursday.

Bank of Tokyo-Mitsubishi and UFJ Bank likely will merge on Jan. 1, while the integration of the other units under the two major financial groups will take place Oct. 1 as scheduled, the sources said.

In a joint statement released Thursday, however, MTFG and UFJ Holdings said no change had been made so far regarding their plan to merge their operations, including BTM and UFJ Bank.