KABUL (Reuters) Easing tension between India and Pakistan would help Western efforts in Afghanistan, but it is up to Islamabad and New Delhi to find their own path toward better ties, the US Special Envoy to Afghanistan and Pakistan said on Sunday. Richard Holbrooke, who was due to fly to India later on Sunday after visiting Pakistan and Afghanistan, said Washington would welcome better relations between Islamabad and New Delhi, but he has no plans to act as a mediator between the two foes. President (Barack) Obama has said publicly that if India and Pakistan improve their relations, he would welcome it, Holbrooke told Reuters in an interview in Kabul before leaving for New Delhi. But its up to them to do it for themselves. We are not intermediating between Islamabad and New Delhi. Every time I go to India people say: 'Are you working on this problem? Are you a messenger? Are you an envoy between the two countries? Holbrooke said. The answer is 'no. He described his visit to India as a 'consultative trip, its not a negotiating trip, unlike his stops in Afghanistan and Pakistan. Asked if better India-Pakistan ties were necessary to resolve the Afghan conflict, Holbrooke said: Is it necessary? ... It would be useful. Asked why, he said: For obvious reasons. In this extraordinary strategic context, every country has a legitimate security requirement which has to be acknowledged if we are ever going to get to a resolution of this 30-year process, he said of the three decades of war in Afghanistan. The Pakistan-India relationship is unique because of its origins on the same day in August of 1947 and the unresolved issue of the territory on their common border, which has been so disputed, he said. Pakistan has legitimate security interests like any nation, based on its ... geo-strategic position, he said. I am not going to get specific about Indias strategic interests. They will speak for themselves. The US Envoy said a video of a Pakistani Taliban leader with the bomber who killed CIA agents in Afghanistan could indicate cross-border links between Afghan, Pakistani and Al-Qaeda militants. He told Reuters in an interview in Kabul that shadowy but unmistakable links between groups exposed by the video helped explain why the United States and its allies were fighting in Afghanistan. The video released this month showed the Jordanian suicide bomber posing with Pakistani Taliban chief Hakimullah Mehsud, before carrying out the Dec 30 attack which killed seven CIA employees, the deadliest strike on the agency in decades. When people say to us, 'why are you fighting in Afghanistan when the goal is to destroy Al-Qaeda and they are in Pakistan? I think this incident highlights the explanation for what we are doing, because there are some shadowy but unmistakeable connections here, he said. The bombing took place at a CIA base in Khost, eastern Afghanistan, where Washington says its main enemies are militants loyal to Jalaluddin Haqqani, a Taliban-allied commander who is believed to be sheltering in s North Waziristan Agency. The video could show the very close links between the Haqqani group, Mehsud, Al-Qaeda, and it underlines the rationale for our strategy, he said. That was a horrifying tape. Theyve all claimed credit for it, he said of the various groups with some possible hand in the CIA attack. Asked whether he had put more pressure on Islamabad to do more in border regions to rout insurgents, Holbrooke said Pakistans military was stretched very thin. I think they are well aware of the fact that the presence on their soil of the Afghan Taliban and its leadership is not in their own security interests. They know how important this is. They are our allies, he added. Islamabad has been asking for additional military assistance to fight insurgents and for the transfer of US military know-how for drones and other equipment, requests that have so far been met with reluctance by the Pentagon. This is an immensely complicated issue and when you talk about it too much, you work against the national interests of the United States and anyone who opposes the terrorists who are still out there, said Holbrooke when asked about this. I am limited in what I can talk about on this subject , but sometimes policies ... have costs and benefits, he said, asked how the drone attacks had affected US-Pakistani ties. They have to be weighed very carefully against the national interest and against the realities. On this issue, I am not going to add fuel to the fire.