New Delhi, Jul 13 (IANS): Congress president Sonia Gandhi would host a lunch for MPs of the UPA and supporting parties a day before July 19 presidential polls, party sources said.

They said the luncheon meeting is aimed at closer interaction between the alliance partners and supporting parties ahead of the presidential election.

Though Congress leaders have expressed optimism about United Progressive Alliance (UPA) candidate Pranab Mukherjee winning the presidential polls by a substantial margin, they are leaving nothing to chance.

A meeting of UPA parties has been called July 14, party sources added.

Both Mukherjee and P. A. Sangma, whose candidature has been supported by parties including Bharatiya Janata Party, AIADMK and Biju Janata Dal, have been touring the country to convass support.

Meanwhile, Nationalist Congress Party Thursday called upon the BJP, AIADMK and the BJD to withdraw support to Sangma as "he had crossed limits of dignity" in the presidential polls.

Sangma had quit NCP to contest the presidential polls.

"It is very unfortunate that P.A. Sangma is not observing decency, decorum and dignity in the Presidential elections," NCP leader D. P. Tripathi told mediapersons here

Tripathi's remarks came in the wake of Sangma's reported comments that Rashtrapati Bhawan was being used as a dumping ground for "failed" former finance minister Pranab Mukherjee.