Adds no comment from Indian Air Force spokesman, background on India-Pakistan relations, paragraphs 2 and 13-16

By Saeed Shah, Idrees Ali

ISLAMABAD/WASHINGTON, May 8 (Reuters) - A top Chinese-made Pakistani fighter plane shot down at least two Indian military aircraft on Wednesday, two U.S. officials told Reuters, marking a major milestone for Beijing's advanced fighter jet.

An Indian Air Force spokesperson said he had no comment when asked about the Reuters report.

The performance of a leading Chinese fighter jet against a Western rival is being closely watched in Washington for insights into how Beijing might fare in any showdown over Taiwan or the wider Indo-Pacific.

One U.S. official, speaking on condition of anonymity, said there was high confidence that Pakistan had used the Chinese-made J-10 aircraft to launch air-to-air missiles against Indian fighter jets - bringing down at least two.

Another official said at least one Indian jet that was shot down was a French-made Rafale fighter aircraft.

Both officials said Pakistan's F-16 aircraft, made by Lockheed Martin LMT.N, were not used in the shootdown.

Delhi has not acknowledged the loss of any of its planes and instead said it carried out successful strikes against what it said was "terrorist" infrastructure inside Pakistan.

World powers from the U.S. to Russia and China have called for calm in one of the world's most dangerous, and most populated, nuclear flashpoint regions.

In France, Rafale manufacturer Dassault Aviation AM.PA and the MBDA AIR.PA, BAES.L, LDOF.MI consortium, which makes the Meteor air-to-air missile, could not immediately be reached for comment on a public holiday.

While Reuters reported on Wednesday that three Indian planes went down, citing local government officials in India, this marks the first Western confirmation that Pakistan's Chinese-made jets were used in the shootdowns.

Pakistan’s Defense minister, Khawaja Muhammad Asif, told Reuters on Thursday that the J-10 was used to shoot down three French-made Rafale planes, which were newly acquired by India.

Altogether, Pakistan says it downed five Indian planes in air-to-air combat.

The Rafale and the model of the J-10 used by Pakistan are both considered generation 4.5 fighter jets, placing them at the leading edge of combat aircraft

Nuclear-armed India and Pakistan have fought three major wars, as well as numerous smaller conflicts.

Blasts rang out across the city of Jammu in Indian Kashmir late on Thursday during what Indian military sources said they suspected was a Pakistani drone attack across the region on the second day of clashes between the neighbors.

Pakistan said earlier on Thursday it shot down 25 drones from India overnight, while India said its air defenses had stopped Pakistani drone and missile attacks on military targets.

(Reporting by Saeed Shah in Islamabad and Idrees Ali in Washington; Additional reporting by Tim Hepher in Paris and Shivam Patel in New Delhi; Editing by Don Durfee and Matthew Lewis)

((Idrees.Ali@thomsonreuters.com; 301-747-8263;))