The Centre on Friday put airports across the country on alert to prevent Italy ambassador Daniele Mancini from leaving India.

New Delhi also decided to downgrade its diplomatic ties with Rome as it asked its ambassador-designate Basant Kumar Gupta not to take up his posting. He was to leave for Rome on Friday. Gupta was named successor to Debabrata Saha, who retired in December.

The diplomatic standoff  also figured at the Friday evening meeting of the Congress core committee, attended by Prime Minister Manmohan Singh and Congress president Sonia Gandhi. The meeting decided that the government should continue its tough stand on the issue. External Affairs Minister Salman Khurshid apprised the meeting of the stand adopted by the government.

The Home Ministry is understood to have told the External Affairs Ministry that a diplomat ceases to retain immunity if he violates the sovereign commitment he has given to the host country.

On February 22, the apex court allowed the two marines, Massimiliano Latorre and Salvatore Girone — accused of killing two Indian fishermen —  to fly to Italy to vote in the February 24-25 election. The four-week time given to them to return expires on March 22.

Khurshid said the apex court order would be complied with by all government agencies.

“The matter will come up before the apex court on Monday and after that the future course of action will be decided. We will know then exactly what is the next step that should be taken,” he said.

Speaking to a TV channel, Khurshid said alert at the airports did not mean that movements of the ambassador within the country were restricted. New Delhi said on Thursday it was reviewing the entire gamut of bilateral ties with Rome.

“The decision of not sending Gupta to assume his position is tantamount to the fact that India wants to keep diplomatic ties with Italy at a level lesser than that of ambassador,” the sources said.