The accused have been identified as Mohammadi Roohullah (30), a resident of Afghanistan, and Gautam Pal (25), a resident of Delhi's Taimoor Nagar area, they said.
Around three kilogram heroin, worth nearly Rs. 12 crore, and 47.5 grams smack were seized from them, police officials said.
According to the police, the two played a key role in supplying and transporting narcotics substances in the national capital and its peripheral areas.
Roohullah was nabbed from the Lajpat Nagar area on Friday and 2.97 kg heroin was found in his possession, senior cop Kumar Gyanesh said, adding that a case has been registered in this connection.
Upon interrogation, Roohullah revealed he had met Habibi Shahabuddin and Sultani Khan at his native place in Afghanistan a few months ago. They are involved in smuggling of narcotics and asked Roohullah to smuggle drug capsules into India by swallowing them, the officer said.
In order to earn quick money, Roohullah agreed to smuggle in the consignment and was promised $2,000 for it, he added.
After reaching his destination at Lajpat Nagar, he expelled the drugs capsules through anal passage. The drugs were meant for private parties in Lucknow and Punjab and unknown people were supposed to collect the consignment from his residence in Lajpat Nagar, Mr Gyanesh said.
In another raid on Thursday, Gautam Pal was arrested near the Modi Mill flyover in Delhi and 47.5 grams of smack was found on him, the officer said.
He used to procure smack at cheap prices from drug-suppliers and supply them to drug-peddlers of Delhi-NCR at high prices, he added.