Growth fears and U.S. government shutdown threat slam stocks

LONDON (Reuters) - World stocks extended a steep sell-off on Friday as the threat of a U.S. government shutdown and further hikes in U.S. borrowing costs compounded investor anxieties over the trajectory of global economic growth.European shares opened in negative territory, following in the footsteps of U.S. and Asian markets. The pan-European STOXX 600 fell over half a percent, continuing its slide towards lows not seen since the end of 2016. [.EU]Most European bourses and industry indexes..