MILITARY installations across the region remained on high alert yesterday as America counted the cost of Tuesday's terror attacks.

At the US spy base at Menwith Hill, in North Yorkshire, military police patrolled the perimeter fence while maintaining a high profile at the main entrances.

Cones prevented vehicles parking near the gates, and drivers' identities were checked thoroughly while sniffer dogs were used to check all incoming vehicles.

Although the US personnel were stunned by the horrifying images from New York and Washington, a spokeswoman said there were no plans yet to hold any special event to remember the dead.

Meanwhile, security was also tightened at Army bases in the area, including barracks around York and Ripon as well as at Catterick Garrison about 40 miles north.

"Obviously, we cannot discuss what precautions we are taking but anyone passing a military base anywhere in the UK is going to notice there are more guards at the gates. The threat is being taken very seriously indeed," said a spokesman yesterday.

North Yorkshire Police have also responded by re-establishing a Silver Command room to deal with security, which will operate in a similar way to the control centre which coordinated the response to last year's floods.

"Its task is to coordinate the response to what happened in America and liaising with others involved in security if necessary.

"However, our role is also to ensure we are visible, with extra patrols out to reassure the public we are looking after their interests," said a spokesman.