Afghan President Ashraf Ghani issued an ultimatum to the Taliban on Tuesday, warning them to embrace peace or "face consequences" after announcing that the death toll from last week's devastating truck bombing had crossed 150.
Ghani has come under mounting criticism over the bombing, the deadliest in Kabul since 2001, with protests and deadly street clashes roiling the Afghan capital as people incensed by spiralling insecurity call for his government's resignation.
Ghani said at the conference that if the Taliban did not begin negotiations soon, he would seek new sanctions against the group as a sponsor of terrorism.
"We are offering a chance for peace but this is not an open-ended offer," Ghani said.
"Time is running out ... this is the last chance: take it or face consequences."
Response to peace conference
The conference, called the "Kabul Process", aims to set the stage for peace talks and clinch an international pact to end "cross-border terrorism."
Hours after Ghani's statement, a bomb blast on Tuesday killed at least seven people in Herat, Afghan police said. Another 15 were wounded in the bombing which took place outside a mosque in the western city. Local media said 10 people were killed
Also on Tuesday, a rocket was fired at what unidentified insurgents claimed was NATO's headquarters. Instead, it landed inside Indian Ambassador Manpreet Vohra's residence in Kabul; no one was hurt.
Separately, an explosion was also heard in the Shash Darak area of the city.
Bringing the Taliban to the table
The Taliban made steady gains in the country since the international military mission declared an end to its combat mission in 2014.
As of late last year, the Taliban contest or control about 40 percent of the country.
Previous international efforts to bring the Taliban to the negotiating table have failed, but diplomats in Kabul hailed Tuesday's conference as a stepping stone to peace.
"The launch of the Kabul Process tomorrow is an important marker for each and every country in the region to show its true support for Afghanistan's aspirations for peace," said British Ambassador Dominic Jermey on Monday.
A spokesman for the Taliban said he was not prepared to make any immediate comment on the conference.
The militants have said no talks are possible until all foreign troops leave.
Kabul has been on edge since the massive tanker bomb last Wednesday ripped through the city's highly-fortified diplomatic quarter, home to the presidential palace and a host of foreign embassies.
The death toll has jumped to more than 150 people, while over 300 wounded were brought to hospitals, many with burns and amputations, Ghani told the conference.
"We are a nation of survivors. Terrorists can shed our blood but they cannot break our will," he said.
The government has accused the Taliban-allied Haqqani Network of carrying out the May 31 attack.