Hyderabad, Sep 13 (IANS): Polling is under way for by-election to the Medak Lok Sabha constituency in Telangana and Nandigama assembly seat in Andhra Pradesh.

Election officials said the polling began in both the constituencies amid tight security at 7 a.m. Voters will be allowed to cast their votes till 6 p.m.

Electronic Voting Machines (EVMs) at few places developed snag, resulting in the delay in start of the polling process. The officials replaced the faulty EVMs.

Over 15.43 lakh voters are eligible to cast their franchise in the prestigious Medak parliamentary constituency, where poll authorities have set up 1,817 polling centres.

Telangana Chief Minister K. Chandrasekhar Rao, whose resignation caused the vacancy, and his wife will cast their votes in their native Chintamadaka village of Siddipet mandal.

About 10,000 security and poll personnel have been deployed in the constituency as part of elaborate arrangements to ensure free and fair elections.

A total of 14 candidates are in fray in Medak but it is mainly a triangular contest. K. Prabhakar Reddy of ruling Telangana Rashtra Samithi (TRS) may have a smooth sailing. He is pitted against BJP-TDP combine's Jagga Reddy and Congress party's Sunitha Lakhsma Reddy.

Polling also began in Nandigama assembly constituency in Krishna district of neighbouring Andhra Pradesh.

Over 1.84 lakh voters are eligible to cast their votes at 200 polling centres.

Four candidates are in fray in Nandigama, a seat reserved for scheduled castes. The ruling Telugu Desam Party (TDP) has fielded Tangirala Soumya, daughter of Tangirala Prabhakar Rao, whose death caused the vacancy.

Soumya is locked in a direct fight against B. Babu Rao of Congress party. The two other candidates are independents.