Story highlights The death toll rises to 60; the number of people wounded climbs to 110

Two groups claim responsibility for bombing, and one promises more attacks

5 kilograms of explosives used, police say; suicide bomber's body parts found

Pakistan and India take part in daily "lowering of the flags" ceremony at border

At least 60 people were killed and more than 110 were wounded Sunday in a Lahore, Pakistan, suicide blast near the country's border with India, police said.

A suicide bomber detonated his vest after a daily parade at the Wagah border crossing, police said. It appeared the bomber entered the parade area as people were leaving and set off an explosive vest near a checkpoint, police said.

Spokesmen for two groups linked to the Pakistani Taliban -- Jundallah and Jamaat-ul-Ahrar -- separately claimed responsibility for the bombing, with the spokesman for the latter, Ehsanullah Ehsan, calling the Jundallah claim "baseless." Ehsan's statement promised more attacks.

"We will soon release the video of this attack," the statement said. "This attack is the revenge of the killing of those innocent people who have been killed by Pakistan Army, particularly of those who have been killed in North Waziristan."

Footage from CNN affiliate GEO News showed authorities scrambling through the streets, some of them ferrying the injured on stretchers to ambulances. Many onlookers were crying as they spoke to reporters.

More than 5 kilograms (11 pounds) of explosives were used in the blast, which was conducted by a male from 18 and 20 years old, Inspector General Mushtaq Ahmad Sukhera of the Punjab police said.

Some of the bomber's body parts were found at the scene, he said. The latest numbers of dead and wounded were reported Monday by Amin Wains, the Chief Capital Police Officer of Lahore.

Authorities were aware of threats of terrorism, and Pakistan's paramilitary security force, the Rangers, was prepared, but the crowds at the border were larger than normal so Rangers weren't able to check everyone as they departed the area, Sukhera said.

Every evening for 55 years at the Wagah border crossing between Lahore and Amritsar, India, Pakistan's Rangers and India's Border Security Force take part in a lowering-of-the-flags ceremony before sunset.

The ceremony, which ends with soldiers folding their countries' flags and shaking hands, draws attendees from both sides of the border, as well as international tourists.

The "beating retreat" ceremony, as it's known, is postponed until Thursday, officials said.