BEIJING, Sept 18 (Reuters) - China announced steps

against nine U.S. military-linked firms on Wednesday over U.S.

weapons sales to Taiwan, freezing their property within China,

in the latest move to put added pressure on the United States to

halt its arms sales to the island.

China has repeatedly called on the White House, an important

international backer and arms supplier for

democratically-governed Taiwan, to refrain from formal dealings

with the island's leadership.

Beijing claims Taiwan as part of its territory.

The steps taken against the firms, including Sierra Nevada

Corporation and Stick Rudder Enterprises LLC, became effective

on Wednesday and will freeze their property within China,

according to a foreign ministry statement.

It described the actions as countermeasures and said they

also applied to Cubic Corporation, S3 Aerospace, TCOM Ltd

Partnership, TextOre, Planate Management Group, ACT1 Federal and

Exovera, the ministry said.

Organisations and individuals within China are prohibited

from engaging in transactions with the firms, the statement

said.

A spokesperson for China's foreign ministry on Wednesday

urged the United States "to immediately stop the dangerous trend

of arming Taiwan.

"Stop conniving and supporting Taiwan independence, and stop

undermining peace and stability in the Taiwan Strait," said

ministry spokesperson Lin Jian at a regular press briefing.

China previously sanctioned and banned firms, including

Lockheed Martin ( LMT ) units, for selling arms to Taiwan.

China had said it was strongly opposed to U.S. arms sales to

Taiwan and urged Washington to withdraw them immediately.

The defence ministry also previously lodged a complaint to

the United States over the matter.

China has ramped up military and political pressure over the

past five years to assert its claims, which Taipei strongly

rejects.