KARACHI: Two workers of the Pak Sarzameen Party (PSP) were killed in an armed attack by unknown pillion riders on the party’s office in Rizvia Society here on Sunday night. According to police, around one dozen armed men, riding six motorcycles, opened indiscriminate fire on the PSP office in Usmania Colony, killing two PSP workers — Azhar Rehmat, 35, and Naeem Ramzan, 40, — and injuring two others, the police said.