By Matt Siegel
SYDNEY, July 25 (Reuters) - Australia will send 100 additional police and some defence force personnel to Europe to join a planned Dutch-led international security force to secure the Malaysia Airlines Flight MH17 crash site, Prime Minister Tony Abbott said on Friday.
The Australian Federal Police (AFP) officers, some of whom will be armed, will join a contingent of 90 AFP officers already in London waiting for a deal with Ukrainian President Petro Poroshenko to be approved by Ukraine's parliament.
"This is a humanitarian mission, with a clear and simple objective," Abbott told reporters. "I expect the operation on the ground in Ukraine, should the deployment go ahead, to last no longer than a few weeks."
Abbott announced on Thursday that 50 police officers had been deployed to London ahead of the mission, but a police spokeswoman said on Friday that the number was 90. It was unclear why the discrepancy had occurred.
On Tuesday, Abbott said that Russian-backed rebels who control the area were tampering with evidence on "an industrial scale" and argued that outside police or possibly military forces were needed to ensure that did not continue.
The Boeing 777 was shot down last week in eastern Ukraine en route from Amsterdam to Kuala Lumpur, killing all 298 passengers and crew on board. Twenty eight Australians were killed. (Reporting by Matt Siegel; Editing by Robert Birsel)