Japan's benchmark stock index plunged 12.4% on Monday, compounding a global market rout set off by investor concerns that the the U.S. economy could be headed for recession.

A report Friday showing hiring by U.S. employers slowed last month by much more than expected has convulsed financial markets, vanquishing the euphoria that had taken the Nikkei 225 to all-times highs of over 42,000 in recent weeks.