"We perceive as a deliberate provocation the US Embassy claims that it has been denied access to the summer house ahead of the deadline," the source told RIA Novosti.
Cargo vehicles are not allowed in the Serebryanny Bor area as it is considered a nature reserve, the source added.
"The Americans simply did not bother to inform the Moscow department of environmental protection in advance…that they were going to send three large trucks there," the source said.
"When the Russian Foreign Ministry urgently resolved the matter on July 31, and security staff wanted to issue permissions for [US] embassy employees to enter… the reserve, they drove away upon command," the source noted.
The source added that the embassy staff was expected to return on Tuesday morning but "US diplomats continued to tell the media that they had allegedly been prevented [from entering the area]."
On Thursday, the Russian Foreign Ministry called on Washington to cut down the number of diplomats and technical staff of diplomatic missions in Russia to 455 people, on par with Russia's diplomatic representation in the United States, by September 1. It also said that from August 1, Russia would suspend the use of all warehouses in Moscow and a compound in the Serebryany Bor park by the US embassy.
On Sunday, Russian President Vladimir Putin said that the personnel of the US diplomatic missions in Russia would be cut by 755 people.
Russia's move came as a response to a series of measures implemented by the United States. Last week, both chambers of the US Congress approved a bill imposing new sanctions on Russia, Iran and North Korea, as well as limiting US President Donald Trump's ability to lift the anti-Moscow restrictions.
In December 2016, Washington adopted sanctions targeting Russia over its alleged interference in the US presidential election, something which Moscow has repeatedly denied, expelling 35 Russian diplomats and seizing two diplomatic compounds used by Russia.
