WARSAW, Poland (AP) — Poland’s government spokeswoman says a new prime minister should be appointed before the end of the month to replace Donald Tusk who will take office as the European Council’s president in December.

Tusk, a 57-year-old historian, has been democratic Poland’s longest-serving prime minister since 2007, with one year to go in his second term. But he needs to resign with his entire Cabinet to take one of the top EU offices, which he was unanimously given at an EU summit last weekend.

Spokeswoman Malgorzata Kidawa-Blonska said Tuesday that Poland should have a new prime minister “before the end of September.” This means the new Cabinet should be in place in October.

Parliamentary Speaker Ewa Kopacz and Defense Minister Tomasz Siemoniak are mentioned as Tusk’s possible successors.

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