An Indian soldier salutes the coffin bearing the remains of Brigadier Ravi Datt Mehta, one of 54 people killed in a July suicide bomb attack at India’s embassy, in Kabul, Afghanistan.

WASHINGTON — U.S. intelligence agencies have concluded that members of Pakistan’s powerful spy service helped plan the deadly July 7 bombing of India’s embassy in Kabul, Afghanistan, according to U.S. government officials.

The conclusion was based on intercepted communications between Pakistani intelligence officers and militants who carried out the attack, the officials said, providing the clearest evidence to date that Pakistani intelligence officers are actively undermining U.S. efforts to combat militants in the region.

The U.S. officials also said there was new information showing that members of the Pakistani intelligence service were increasingly providing militants with details about the U.S. campaign against them, in some cases allowing militants to avoid U.S. missile strikes in Pakistan’s tribal areas.

Concerns about the role played by Pakistani intelligence not only has strained relations between the United States and Pakistan, a longtime ally, but also has fanned tensions between Pakistan and its archrival, India. Within days of the bombings, Indian officials accused the Directorate of Inter-Services Intelligence, or ISI, of helping to orchestrate the attack in Kabul, which killed 54, including an Indian defense attache.

This week, Pakistani troops clashed with Indian forces in the contested region of Kashmir, threatening to fray an uneasy cease-fire that has held since November 2003.

The New York Times reported this week that a top CIA official traveled to Pakistan in July to confront senior Pakistani officials with information about support provided by members of the ISI to militant groups. It had not been known that U.S. intelligence agencies concluded that elements of Pakistani intelligence provided direct support for the attack.

U.S. officials said that the communications were intercepted before the July 7 bombing, and that the CIA emissary, Stephen Kappes, the agency’s deputy director, had been ordered to Islamabad, Pakistan’s capital, even before the attack. The intercepts were not detailed enough to warn of any specific attack.

The government officials were guarded in describing the new evidence and would not say specifically what kind of assistance the ISI officers provided to the militants.