"Dear PM, the Constitution is reaching you soon. When you get time off from dividing the country, please read it," the Congress tweeted.
In a series of tweets, it slammed the central government on the CAA. "It is important to remember that it is enshrined in our Constitution that all persons are protected from discrimination of any form. Therefore, any attempt to draft laws based on discrimination is unconstitutional," it said.
The Congress also organised "the Preamble reading" programmes in all state capitals.
Earlier on the eve of the R-Day on Saturday, interim party chief Sonia Gandhi said the constitutional values were no longer safe.
"Today, the Constitution and its values are being attacked by way of a concerted and vicious conspiracy. Constitutional principles are being systematically encroached upon as also the independence of constitutional institutions is being scuttled at the whims of autocratic authoritarianism," Gandhi said in the statement.
Urging the citizens to protect the Constitution, she said it was the duty of every citizen to stand united in defence of the Constitution.
Gandhi said the agricultural sector and farmers were on the verge of devastation, the youth were ravaged by unfathomable unemployment and the country was facing recession and closure of factories.
( With inputs from IANS )