PARIS (Reuters) - A 10 billion euro ($10.66 billion) Franco-German fund to pay for tighter security, external border controls and caring for refugees could be set up within weeks if there is enough political will, a source close to the French economy minister said on Tuesday.

French Economy Minister Emmanuel Macron and his German counterpart, Sigmar Gabriel, have proposed setting up the fund in a letter to President Francois Hollande and German Chancellor Angela Merkel, Macron said in Berlin on Monday.

In the letter seen by Reuters, the two ministers said the fund could receive 10 billion euros over three years to deal with emergency situations and have a very simple, efficient governance based on the economic weight of each country. Other European Union countries would be welcome to join.

"The idea is to send a quick signal. If we wait for an update of the European Union's plurianual financial plans, we won't have anything until 2017. And the situation is urgent," the source close to Macron said.

"It's not a challenge to action at the European community level, but it would complement and guide it," the source said. "The Juncker plan was set up in four months. This could be technically done in a few weeks. The real question is the political will."

The two ministers' initiative comes about five months after another joint proposal by the pair to set up a common euro zone budget, which was not immediately followed up by their respective leaders.

But the source said the refugee crisis in Germany and the attacks by Islamist militants that killed 130 people in and around Paris earlier this month had made the need for a more collaborative approach to current crises more pressing.

Macron said on Monday that he and Gabriel would present a more detailed text by mid-December that would build on proposals they made in June regarding closer integration of the euro zone.