Lucknow: A young man in his twenties put a gun to his temple and pulled the trigger while speaking on his cellphone on the Aligarh Muslim University campus in a Valentine's Day suicide that police said had a "love angle" to it.

Another young man, also in his twenties, however, chose to take his frustrations out on another.

The undergraduate student from a village in Hapur district, 100km from Aligarh, pulled out a revolver and fired at a woman after she refused his proposal to elope, turning a tiff into a traumatised trip to hospital.

The suicide in Aligarh followed four hours later, about half an hour after noon, as February 14 left behind a sour taste for some in Uttar Pradesh.

The police didn't reveal more but claimed a "love angle", saying the 20-year-old, identified as Rohit Kumar Singh from Bhatpura in Bijnore district, was there to meet someone on Valentine's Day. Rohit worked in a factory in Haridwar.

"Some people had seen the youth wandering near the engineering college crossing on the Aligarh Muslim University campus," circle officer Sanjeev Dixit said. "He was carrying a backpack. While still on the mobile, he fired in the air from a country-made pistol and later pointed it at his own temple. Some passers-by took him to hospital where he was declared brought dead."

Rohit's father Rotam Singh told Bijnore police his son had left home six days ago. "Rohit said he was going to Bareilly to attend a wedding. From there he had to go to Mathura to meet another friend," the father was quoted as telling investigators.

Earlier in the day, around 8.30am, the 22-year-old undergraduate arts student had walked up to the woman, revolver in his pocket, in Putha-Hussainpur village under Pilkhua police station.

"We had an affair for the last five months. Today I went to a local shop to buy groceries when he suddenly came up and asked me to elope with him. He pulled a revolver and fired at me when I refused," the victim, admitted with a shoulder injury, told reporters from her hospital bed in Hapur, 550km west of Lucknow.

Pawan Kumar, deputy superintendent of police, Pilkhua, said the accused had been identified as Sagar Kumar, 22. "He escaped from there after firing at the girl. We have constituted a police team to arrest him soon."

The officer said the accused was an undergraduate student and the victim an intermediate dropout, both of them from the same village.

The day also saw all the gates of Lucknow University remain shut as more than the usual number of private security guards stood near the boundary walls to prevent students from entering.

Vinod Singh, chief proctor, had issued a notice on Tuesday saying February 14 was a holiday on account of Mahashivaratri and students "influenced by western culture and (who) intended to celebrate Valentine's Day" shouldn't visit the campus.

He had later dropped the reference to Valentine's Day from the advisory.

Vigilant Shiv Sena and Bajrang Dal members patrolled the streets of several cities in west Uttar Pradesh, including Agra and Muzaffarnagar, to prevent lovers from meeting.