The leader of German Chancellor Angela Merkel's Bavarian allies has reportedly rejected a deal she secured in Brussels last week to slash migration, escalating a crisis that threatens to bring down her conservative alliance.

Merkel has been under pressure for weeks from Bavaria's Christian Social Union (CSU), the sister party of her centre-right Christian Democratic Union (CDU).

The CSU, which faces a stiff challenge from the far-right Alternative for Germany (AfD) party in October's regional polls, has been demanding a significant hardening of Germany immigration policy.

Amid the increasing tensions, Merkel and the rest of the European Union leaders hammered out on Friday a vaguely-worded deal to share out refugees on a voluntary basis and create "controlled centres" inside the bloc to process asylum requests.

CSU leaders gathered in Munich from 3pm (13:00 GMT) to decide their response to the EU deal.

Party sources told AFP news agency that Horst Seehofer, interior minister and leader of the CSU, told aides he was unhappy with the accord and complained to that he had endured a "conversation with no effect" with the chancellor on Saturday. Agencies