US President Donald Trump termed rising tension between India and Pakistan a shame, while Secretary of State Marco Rubio spoke to officials in the nuclear-armed rivals after India attacked several sites in Pakistan and Pakistan-administered Kashmir.

India is an important US partner for Washington, which aims to counter China's rising influence, while Pakistan remains an ally, despite its diminished importance after the US withdrawal from neighboring Afghanistan in 2021.

Pakistan said it was mounting a response to India's military actions late on Tuesday, which followed an Islamist militant attack that killed 26 in the Indian-administered side of the Himalayan region on April 22.

"It's a shame, we just heard about it," Trump told reporters at the White House. "I guess people knew something was going to happen based on a little bit of the past. They've been fighting for a long time." He added, "I just hope it ends very quickly."

US Secretary of State Marco Rubio said on X he was monitoring the situation closely, while adding that Washington would continue to engage the Asian neighbors to reach a "peaceful resolution." The State Department said Rubio spoke to the national security advisers of both nations, urging "both to keep lines of communication open and avoid escalation."

Top US leaders, including Trump, offered support to India after the April 22 attack. American officials did not directly blame Pakistan. Last month, analysts said Washington may leave India and Pakistan on their own in the early days of the tension, in part because it has a lot to deal with in achieving diplomatic goals in Russia's war in Ukraine and Israel's war in Gaza.

India and Pakistan will figure out relations between themselves, Trump said on April 25: "They'll get it figured out one way or the other." Earlier, State Department spokesperson Tammy Bruce described the situation between the two countries as “a dynamic, serious issue.”

Japan, too, weighed in on the matter. Chief Cabinet Secretary Yoshimasa Hayashi issued a strong condemnation of the Pahalgam terror attack and called on both nations to avoid further confrontation. “In regard to the terrorist act that occurred in Kashmir on April 22, our country firmly condemns such acts of terrorism. Furthermore, we express strong concern that this situation may lead to further retaliatory exchanges and escalate into a full-scale military conflict. For the peace and stability of South Asia, we strongly urge both India and Pakistan to exercise restraint and stabilise the situation through dialogue,” he stated.