Dalili died suddenly on Tuesday from a heart attack after being hospitalized in Doha on Monday.
In a series of tweets early Thursday, Khalilzad said Dalili had been “indefatigable” and had been deeply involved in advancing the peace process.
“I met with him often to seek his insights. His positive engagement with the negotiating teams and US and other diplomats will be sorely missed.
“Let us all honor his commitment to peace by redoubling our efforts,” Khalilzad said.
He also passed on his condolences to his family, the Afghan community in Qatar, and his friends and admirers across Afghanistan.
Khalilzad also pointed out that Dalili had been an effective advocate for strong bilateral ties with Qatari leaders.
Earlier this week, officials from the High Council for National Reconciliation said Dalili’s death was a big loss to Afghanistan and the current peace process.
HCNR spokesman Faraidoon Khwazoon said Dalili had worked hard to make the Afghan peace process a success.
Dalili was appointed Ambassador to Qatar in February 2019 and was known for working tirelessly on the peace process initiative and around strengthening relations with Doha.