(CNN) - Russia has stepped up spying efforts since the election, according to current and former U.S. intelligence officials.
The officials said they believe the Russians feel emboldened by the lack of a significant retaliatory response from the Trump and Obama administrations.
Since November, U.S. intelligence and law enforcement agencies have detected an increase in suspected Russian intelligence officers entering the U.S. under the guise of other business.
In December, the U.S. expelled 35 Russian diplomats suspected of spying in retaliation for election-meddling.
But they said the Russians are believed to now have nearly 150 suspected intelligence operatives in the U.S.
Copyright 2017 CNN. All rights reserved.