ISLAMABAD, May 26 (AFP) - Pakistan's defence has become "invincible" after the nuclear tests last year in response to India's atomic detonations, Prime Minister Nawaz Sharif said Wednesday. "We do not rely on others any longer" for the country's defence, the prime minister told a women's convention held here as part of ongoing celebrations of the May 28 anniversary of the explosions. Sharif said the demonstration of nuclear capability raised the nation's status internationally and made Pakistan's defence "invincbile." His statement coincided with reports of escalating tensions in the Himalayan region of Kashmir. After more than two weeks of cross-border artillery duels in Kashmir, the situation took a new turn Wednesday as India launched air strikes on its side in the Kargil sector against Moslem militants. Later an official statement in New Delhi warned Pakistan that India would take "appropriate" action if Islamabad intervened in its air strikes. Pakistan's foreign ministry, blaming India for the escalation, vowed all necessary defensive measures. Sharif, downplaying the economic fallout of the tests which triggered international sanctions against both countries, said those who had predicted an economic collapse were proved wrong. He said despite "immense" international pressure, he took an "honourable and bold decision" which had "proved correct." Pakistan is emerging from economic difficulties gradually, he said, adding that his government was focusing its energies on achieving national prosperity.  