The Election Commission yesterday announced the schedule for Presidential poll under which counting of votes will be held on July 21.

A contest for the top constitutional post appears on the card with the country's ruling coalition Congress-led UPA set to announce its candidate to be challenged most likely by Vice President Bhairon Singh Shekhawat, a senior BJP leader, who is expected to contest as an independent candidate backed by main opposition NDA.

The UPA Presidential candidate will be a senior Congress leader with Indian Home Minister Shivraj Patil, considered a staunch loyalist of party chief Sonia Gandhi, the front runner. Among other senior Congress leaders who are front-runners for the race are External Affairs Minister Pranab Mukherjee, Karan Singh and Power Minister Sushil Kumar Shinde.

All allies of Congress in UPA have pledged their support to a Congress nominee for the post and so have the Left parties, which provide crucial outside support to the government of Prime Minister Manmohan Singh.

However, the Left have openly favoured Pranab Mukherjee as their choice for Presidential candidate but Congress is understood to be unwilling to spare him because of his importance in managing the ruling coalition.

The UPA is expected to come out with formal announcement of its candidate in a few days and NDA is likely to formally declare its stand on June 18whether it will go for a consensus with the ruling alliance or support Shekhawat as an independent.

The Electoral College for Presidential poll comprises members of Lok Sabha and Rajya Sabha, the two houses of Indian Parliament, and those of legislative assemblies in the states.

Smaller regional parties like Samajwadi Party, Telugu Desam Party and AIADMK, which are neither part of UPA nor of NDA, would announce their stand on Presidential choice on June 18.