A country-made pistol, three knives and two live cartridges were recovered from their possession, police said adding a tempo was also impounded.
The four arrested persons, wanted in several robbery cases, were identified as Bilal, Mushid, Deepak and Dinesh, residents of Gautam Budh Nagar, Hapur, Ghaziabad and Bijnor respectively, police said.
"Acting on a tip-off that four persons were coming to Masuri area near Galand crossing this morning, police laid a trap and arrested all of them.
They used to rob houses locked from outside at night and also passengers at gun-and-knife-point, he said.
"Police are interrogating them to get leads about hideouts of their accomplices who will soon be arrested," the officer said.
