Seeking higher rents from tenants moving into new buildings has become "difficult" amid the economic slowdown resulting from the credit crisis, according to a senior official of Mitsubishi Estate Co.

Mitsubishi Estate, the owner of about 30 buildings in areas adjacent to Tokyo Station and Japan's largest developer by market value, earned record operating profit on rising leasing income for the third straight year in the period ending last March.

It was forecasting a fourth year of record profits until the credit crisis struck, prompting a downward revision Oct. 31.