Pakistan’s top political and military leaders on Wednesday are condemning Indian airstrikes that they said killed 26 people and say the nation is weighing whether to retaliate, while Communist China says it is ready to play a role in easing tensions in the dispute.

India had fired missiles into Pakistani-controlled territory in several locations early Wednesday, as the overall death toll increased to 31 people in what Pakistan’s leader called an act of war. 

India also claims there are casualties from Pakistani fire in the Indian-controlled portion of Kashmir.

India said it struck infrastructure used by militants linked to last month’s massacre of tourists in the Indian-controlled portion of Kashmir. At least seven people died in Indian-controlled Kashmir from artillery exchanges.

Pakistan said at 26 people died in the missile strikes and five from artillery exchange along the Line of Control that separates the two countries in Kashmir. It said another five were killed in artillery fire near the Line of Control.

Pakistan’s National Security Committee, led by Prime Minister Sharif, said in a statement that the Indian strikes were carried out “on the false pretext of the presence of imaginary terrorist camps” and deliberately targeted civilian infrastructure, including mosques.

“These unprovoked and unjustified attacks martyred innocent men, women and children,” the statement said.

Pakistan’s military responded to the strikes, the statement added, by downing five Indian fighter jets and surveillance aircraft.

The government said Pakistan reserves the right to respond “in self-defense, at a time, place, and manner of its choosing,” and that the armed forces have been authorized to take “corresponding actions” to avenge what it called a violation of the country’s sovereignty.

Pakistan claimed it shot down several Indian aircraft in retaliation, including three top-line fighter jets. Two planes fell onto villages in India-controlled Kashmir. One fell in northern Punjab state.

Tensions have soared between the nuclear-armed neighbors over last month’s militant attack on tourists in the Indian-controlled portion of Kashmir.

India has moved to punish Pakistan after accusing it of backing the attack in Pahalgam, which Islamabad denies. The region has been split between India and Pakistan since 1949 and is claimed by both in its entirety.

China expressed “regret” over military action taken by India on Wednesday, a Foreign Ministry spokesman, Lin Jian, said during a regular press briefing in Beijing.

“India and Pakistan are neighbors that cannot be moved, and both are also neighbors of China,” Mr. Lin said. “China opposes all forms of terrorism and calls on both India and Pakistan to prioritize peace and stability, remain calm and exercise restraint, and avoid actions that could further complicate the situation.”