Some eight labourers were carrying out the construction work when the incident happened in Sangrah area, Additional SP Bhagat Ram Thakur said.
"Two workers were buried alive when sand and mud suddenly started falling from the hill," an eye-witness said.
Others were rescued by fellow labourers, the Additional SP said adding a probe had been ordered to ascertain the casue of the mudslide.
In the same district, the body of a 15-year-old boy, a resident of Haryana, was found floating in a river near NCL colony, police said.