They are said to have approached a police officer manning the gate with some wares they said they were selling before grabbing his gun and butting him with it, and then entered the home.
Gunfire has continued at the house, which is surrounded by police.
Security forces are trying to establish if there are still attackers in the deputy president's "expansive" home near the town of Eldoret, some 312 kilometres northwest of the capital Nairobi, a senior police officer said.
NTV News also showed footage of heavily armed officers at the scene responding to the attack.
At least one Kenya's General Service Unit (GSU) officer was injured in the clashes, the media outlet added.
Police and officials from Ruto's office were not available for immediate comment.
The motive of the attack was unclear.
According to Capital FM Radio, unknown gunmen struck the home around noon Saturday, moments after Ruto left to campaign with the president for re-election in the August 8 vote.
"It sends shivers in the country given that DP's home is among the well-guarded and that a gunman can have courage to attack baffles".