US State Department officials have drilled out locks to inspect the former Russian consul general's Seattle residence, a day after Russian staff vacated the site, amidst claims that among them were spies plotting revenge attacks against expat 'traitors'.

President Donald Trump's administration announced last month the diplomatic outpost would be closed and 60 Russian diplomats expelled nationwide to punish Moscow for its alleged role in poisoning an ex-spy in Britain.

A locksmith behind a blue tarp drilled out the front gate's lock on Wednesday, and that US officials moved on to the residence's front door and a basement door, The Seattle Times reported.

The Russian Embassy objected on Twitter, describing it as an invasion. 

The Russians own the building and the US owns the land it sits on.

The State Department said it conducted a residence walk-through to ensure the Russians had left.

It took the locksmith about 15 minutes before he was able to remove the locks to the front gate, according to the Times.

The residence is located at 3726 E. Madison Street in Seattle. 

The property, a three-story mansion with beautiful gardens that has been used mainly as a venue to host receptions, has been appraised at just over $3.8million, according to local tax records. 

'We believe that one day it will be returned to us,' said Nikolay Pukalov, head of the consular division of the Russian Embassy. 

'Our flag is above this property and it will remain there.'

The State Department said it was doing inspections 'to secure and protect the facilities and to confirm the Russian government personnel had vacated the premises.'

Read more on Dailymail.