NEW DELHI, (AP) – Indian and Pakistani leaders pressed ahead Tuesday with peace efforts after twin bombs sparked a fire killing 68 people aboard a train in an apparent attempt to disrupt relations between the two longtime rivals.

Meanwhile, authorities released sketches of two men suspected of planting the bombs, which destroyed two coaches on the Samjhauta Express about an hour after the train left New Delhi on its way to the Pakistan border.

The men boarded the train in New Delhi Sunday and soon began arguing with the conductor, saying they were on the wrong train. Both were allowed to jump off when it slowed down about 15 minutes to 20 minutes before the crude bombs detonated, said Sharad Kumar, a senior police official.

The attack “is the handiwork of a militant outfit, but we don’t know which group is involved,” he told reporters.

Pakistani Foreign Minister Khursheed Kasuri was expected to arrive in the Indian capital later Tuesday for previously scheduled talks.

He was to visit a hospital in New Delhi treating Pakistanis seriously injured in the attack before meeting his Indian counterpart Pranab Mukherjee and Prime Minister Manmohan Singh on Wednesday.

Speaking to India’s CNN-IBN television, Kasuri called the bombing a “terrible act of terrorism” and said “the peace process must go on with greater vigor and greater determination.”

Authorities say two suitcases packed with crude unexploded bombs and bottles of gasoline were found in undamaged train cars, indicating the fire had been sparked by similar devices.

R.K. Kaushik, the Haryana state government’s expert on ballistic and explosive materials, told The Associated Press it was too early to determine who was responsible for the attacks.

“The people who are involved in carrying out this attack appear to be well trained. The method used to carry out this attack — low intensity explosives along with incendiary material — is the best possible way to attack a train,” Kaushik said.

The train was supposed to head from New Delhi to Atari, at the Pakistani border, without any stops, and the revelation that two were allowed to get off appeared to highlight what most passengers already know — that security on the train and at the stations is cursory at best.

In further signs of lax security, Kumar told reporters that 13 passengers made it to the Pakistani side of Atari without passports.

“There is no security at all at the station,” Ati-ur-Rahman said as he waited Monday for word about his missing cousin who was headed for Lahore, the line’s final stop in Pakistan. “There are only a few rude constables and all they’re looking for is a few hundred rupees. They don’t check anything.”

Meanwhile, a Pakistani passenger on the train was detained for questioning, Indian officials said.

“He was found in a drunken state and he’s being questioned. But his account has been inconsistent and we have no definite conclusions yet,” said Bharti Arora, a senior Haryana state railway police official. The man is a resident of Karachi, Pakistan, she said, declining to provide further details.

The death toll rose to 68 on Tuesday after a badly burned passenger succumbed at a hospital in New Delhi, said N.C. Wadhwa, a government official. Most of the dead were Pakistani.

Witnesses described a horrific scene as the train stopped on an isolated stretch of railway near the village of Dewana, about 50 miles north of New Delhi. As on most Indian trains, the windows of many cars are barred for security reasons, sealing in many victims, and officials said at least one door was fused shut by the heat.

The train was traveling from New Delhi to Atari, the last station before the Pakistan border. At Atari, passengers switch to a Pakistani train that takes them to Lahore, Pakistan.

The New Delhi-Lahore train link was suspended after a 2001 attack on the Indian Parliament that India blamed on Pakistan and which nearly led to a war between the two. But relations between the nuclear-armed neighbors have improved, and the train service — restarted in 2004 — is one of the most visible results.

Their enmity focuses on Kashmir, a largely Muslim Himalayan region divided between them but claimed by both. More than a dozen militant groups have been fighting in Indian Kashmir for nearly two decades, seeking the region’s independence or its merger with predominantly Islamic Pakistan. More than 68,000 people have died.