Indian Prime Minister Narendra Modi concluded the West Coast leg of his official visit to the U.S. with a speech at San Jose's SAP Center, to a rousing welcome from thousands of Indian Americans who chanted "Modi, Modi, Modi," on Sunday.

Modi, whose California trip to woo technology leaders -- from Cisco to Tesla -- to invest in India is already being widely seen as a big hit, used the evening's speech to draw attention to two broader challenges.

"Today there are two major challenges before the world. One is terrorism and the other is global warming," he said, speaking in Hindi. "And it is my belief that if the world's forces that value humanity unite, if the people who believe in humanitarian values unite, then we can defeat terrorism as well as save the planet from global warming."

India has accepted these challenges and is "fully prepared" to tackle them, Modi said, adding that his government was putting pressure on the United Nations to speedily resolve the problem of defining terrorism.

"The UN is celebrating its seventieth anniversary, but hasn't yet been able to agree on the definition of terrorism," he said, adding: "If it takes so much time to even define terrorism, how long might it take to tackle it?"

In the absence of the globally accepted language and definitions on terrorism, "today there are dealings in good terrorism and bad terrorism," and in such a scenario it is not possible to combat the problem, he said.

"It must be clear in the eyes of the world, who supports terrorism, who is for humanity ... once and for all, it must be in black and white," he said. "Terrorism is terrorism."

The Indian prime minister, who is continuing India's long-standing demand for a permanent seat at the United Nations Security Council, said the U.N. couldn't afford to wait much longer and it was the organization's responsibility to define the language on dealing with global terror.

"Once you have a clear picture, a clear road map will also emerge," he said.

Modi, who participated in a town hall at Facebook's headquarters earlier on Sunday, also wrote on a wall at the company, flanked by CEO Mark Zuckerberg and COO Sheryl Sandberg: "Ahimsa (non violence) is the greatest dharma (tenet), satyameva jayate (May truth prevail)," he wrote.