Chennai: With political parties in Tamil Nadu stepping up pressure on the Union government to boycott Commonwealth Heads of Government Meeting (CHOGM) scheduled to be held in Colombo later this month, Union finance minister P. Chidambaram met Dravida Munnetra Kazhagam (DMK) chief M. Karunanidhi here on Saturday and said no decision has been taken as yet on the Prime Minister's participation in the meet.