The Communist Party of India-Marxist will not withdraw support to the United Progressive Alliance government at the Centre despite differences with it on issues like the Special Economic Zone policy and Foreign Direct Investment in retail as this would allow the BJP to make a comeback, Marxist partriarch Jyoti Basu said on Friday.

"Despite differences on fundamental issues, we are not thinking of withdrawing support to the UPA government for the simple reason that the BJP will use the opportunity to stage a comeback to power," Basu told media persons after a meeting of the state CPI-M secretariat in Kolkata.

Noting that the CPI-M will oppose UPA's policies both inside and outside the government, he said his party has not discussed the issue of withdrawing support to the Central government.

Basu also accused the UPA of deviating from the common minimum programme for governance, and said this 'was causing concern among Left parties.'

There were also differences among Left Front partners on SEZs and they will meet to sort out these out, he said.      

CPM's allies � Revolutionary Socialist Party and Forward Bloc -- are totally opposed to the setting up of SEZs.

The party was annoyed over decisions by an empowered group of ministers to keep intact 'exorbitant and unjustified tax concessions,' fix the upper limit of multi-product SEZs at 5,000 hectares and allow developers to directly purchase land from farmers.