DAKAR/CONAKRY - Guinea has blocked a shipment of heavy weapons to Mali fearing they could end up in the wrong hands, Guinean and regional diplomats said on Thursday, a further sign of distrust between regional powers and Mali's former junta.

The weeks-long weapons stand-off underscores a deep regional crisis as Mali's neighbors and Western nations fear a new global security threat but are struggling to respond to it.

Rebels dominated by Islamists - including al-Qaida - have taken over the north, and Mali's military coup leaders, despite handing power to civilians in April, are widely suspected of pulling levers of power behind the scenes.