New Delhi, July 21 -- International students currently outside the United States for academic breaks have been advised by their universities to return before 15 September to remain under the existing immigration framework, according to an NDTVWorld report.

The advisory, which also affects Indian students, comes ahead of the US Department of Homeland Security's (DHS) Final Rule, which will replace the long-standing Duration of Status (D/S) system for F and J visa holders.

Under the new framework, international students will be admitted to the US for a fixed period of up to 4 years, rather than being allowed to remain for the duration of their academic programme.

In a notice to students, Columbia University said: "This final rule has a 6...