The German government said on Sunday it had stopped all freight to Germany from Yemen after it was discovered that a bomb found on a US-bound cargo plane was trans-shipped at Cologne-Bonn airport.

'No more air mail parcels or freight from Yemen will be allowed into Germany,' Transport Minister Peter Ramsauer said in a statement, adding that authorities were instructing airlines, logistics firms and delivery services to act accordingly.

Yemeni forces on Saturday arrested a woman believed to be involved in sending explosive packages bound for the United States that triggered a global security alert.

Separately, Germany's federal crime office (BKA) said it had delivered the decisive tip to British authorities about the parcel bomb intercepted in Britain early on Friday.

The bomb was one of two found in packages from Yemen addressed to synagogues in Chicago in the United States. The other was intercepted in Dubai.

A spokeswoman for the BKA said by the time German authorities had been informed about the suspect device on board the shipment, it was too late to intervene locally.

'It was already on the way to Britain,' she said. 'We managed to inform our partners in London so that they were able to look specifically for the package and find it.'

The tip was the result of international co-operation with security sources, she said, declining to give further details.-Reuters