MILAN (Reuters) - Italy's market watchdog Consob plans to summon top executives of Monte dei Paschi <BMPS.MI> and veteran banker Corrado Passera to explain the circumstances that led to Passera's dropping his rescue plan for the bank, a source close to the matter said.

The source did not say when the two sides would be heard.

In a letter to the bank's board released to the media on Tuesday, Passera said he had decided to drop his plan and accused the bank of obstruction.

Monte dei Paschi replied in a statement Passera's claims were groundless, adding his proposal was non-binding, had been put together for investors who had not been named and was not yet "solidified".

A Consob spokesman said the watchdog was "speaking to all the parties involved."

(Reporting by Paola Arosio, editing by Silvia Aloisi)