TOKYO, Aug 5 (Reuters) - Japanese Finance Minister Shunichi Suzuki said on Monday the government was cooperating with the central bank and closely monitoring markets with a sense of urgency.

"It's hard to say what is behind the decline in stocks," Suzuki told reporters, adding that authorities were monitoring stock market moves with "grave concern". (Reporting by Makiko Yamazaki and Satoshi Sugiyama; Writing by Leika Kihara; Editing by Jacqueline Wong)