Two men of US and Canadian citizenship are among those being detained over the Indian Parliament attack.
They were dragged off planes bound for America and Canada in New Dehli. They are both of Pakistani origin.
Fourteen people are being held by police investigating the attack which left 12 people dead, including all five attackers.
Shafique Verghy, a Canadian national, and Feroze Dosani, a US national, were taken off flights at Indira Gandhi International Airport.
In addition, three people have been arrested from Indian-administered Kashmir and nine others held in a nationwide swoop on the suspected hideouts of Islamic rebels.
Indian officials claim they have intercepted radio messages passed between the terrorist groups Lashkar-e-Taiba and Jaish-e-Mohammad, which suggest both the outfits were involved.
The two organisations were reportedly congratulating each other for "accomplishing the mission", military sources said.
India has blamed the Pakistan-based Lashkar-e-Taiba organisation for the attack and asked Islamabad to arrest its leaders and seize its financial assets.
Pakistan has demanded India provide evidence that Lashkar-e-Taiba members were behind the attack.