The United States has complained to Russia about a mounting campaign of harassment and intimidation of American diplomats and their families in Moscow, the State Department said, according to AFP.

Among those to raise objections, U.S. Secretary of State John Kerry discussed the issue with Russian President Vladimir Putin in March, State Department spokeswoman Elizabeth Trudeau said.

"Over the past two years, harassment and surveillance of our diplomatic personnel in Moscow by security personnel and traffic police have increased significantly," she told reporters during a news conference.

She was commenting about a report by The Washington Post on Monday, June 27 that described a series of actions by Russian security and intelligence services, including following diplomats and their family members, appearing at social functions uninvited and paying for negative media stories.

"We see an increase and we take it seriously," Trudeau said on Monday, according to AFP.

Moscow accuses the United States of harassing its own diplomats and says it takes reciprocal measures only in response.

"We have recently felt a significant increase in pressure on the Russian embassy and consulates general of our country in the United States," Russia's TASS news agency reported Russian Foreign Ministry spokeswoman Maria Zakharova as saying last week.

Russian diplomats "regularly become the objects of provocations by the American secret services, face obstacles in making official contacts and other restrictions," such as travel, she added.