In a strong message to Pakistan, US Defence Secretary Jim Mattis has said it is time for "every responsible nation" to support the efforts of the UN, Prime Minister Narendra Modi and all those who are trying to maintain peace in South Asia.
Pakistan must take on a substantive role in peace talks with the Taliban if the war in neighbouring Afghanistan is to be ended, he said.
Mattis was responding to a question from reporters about a letter written by President Donald Trump to Pakistan Prime Minister Imran Khan, seeking his support in the peace process in Afghanistan. In his letter, Trump made it clear that Pakistan's full support over the issue "is fundamental" to building an enduring US-Pakistan partnership.
"We're looking for every responsible nation to support peace in the sub-continent and across this war in Afghanistan that's gone on now for 40 years," he told reporters at the Pentagon on Monday as he welcomed Defence Minister Nirmala Sitharaman for talks.
"It's time for everyone to get on board, support the United Nations; support Prime Minister Modi's, (Afghan) President (Ashraf) Ghani and all those who are trying to maintain peace and make for a better world here," Mattis said.
"We are on that track. It is diplomatically led as it should be, and we'll do our best to protect the Afghan people," he added.
Since taking office, Trump has been very critical of Pakistan's lax attitude towards combatting terrorism.
Last month Trump said Pakistan does not do "a damn thing" for the US, alleging that Islamabad had helped al-Qaeda chief Osama bin Laden hide near its garrison city of Abbottabad.
Ties between the US and Pakistan strained after Trump, while announcing his Afghanistan and South Asia policy in August last year, hit out at Pakistan for providing safe havens to "agents of chaos" that kill Americans in Afghanistan and warned Islamabad that it has "much to lose" by harbouring terrorists.
In September, the Trump administration cancelled $300 million in military aid to Islamabad for not doing enough against terror groups like the Haqqani Network and the Taliban active on its soil.
The Trump administration, in the recent months, has intensified its efforts to seek a negotiated settlement of America's longest war in Afghanistan where the US has lost over 2,400 soldiers since late 2001, when it invaded the country after the 9/11 terror attacks.
The Taliban are fighting to flush out US-led international forces and re-establish their regime in Afghanistan after their ouster in 2001.