The Soviet Union has moved medium-range ballistic missles into Afghanistan, armed with both nuclear and conventional warheads, according to sources in Kabul quoted by a respected Indian journalist just returned from there.

H. N. Kaul, a senior correspondent of the independent Press Trust of India, wrote yesterday that the same "highly placed sources" also put current Soviet troop strength in the country at 110,000.

Kaul left Kabul Friday, one of the last noncommunist correspondents to depart. His report was considered significant here because of his senior status and also because India's professed neutrality in the Afghan crisis generally has shown a pro-Soviet tilt.

While no other sources was given for Kaul's report, the current issue of the semiweekly India Today magazine quotes diplomatic sources in Kabul on the presence of Soviet missiles with nuclear warheads.

Kaul cited two possible reasons for te alleged missile emplacement: as a counter to U.S. missiles said to be carried by intercontinental B52 bombers, or to give the Soviets favorable launching sites to control the oil lanes of the Persian Gulf and Strait and Hormuz.

Elaborating on the troop count, Kaul said his sources "estimate four to five Russian divisions are poised along the Iranian border." Soviet divisions run to 10,000.