India's new prime minister reassured his Chinese counterpart on their nations' close ties and said he was eager to work closely on any outstanding issues with Beijing.

In his first phone call with a foreign head of government Thursday, Narendra Modi, who took office earlier this week, told Chinese Premier Li Keqiang that China is "always a priority in India's foreign policy," according to Mr. Modi's office, while Mr. Li said his government wants a "robust partnership" with India.

The chat between leaders comes after Mr. Modi took a tough stance on the campaign trail toward Beijing. At an election rally in February near India's disputed border with China, he told the Chinese to abandon any territorial ambitions. He said China would have to "leave behind its mind-set of expansion" and should instead focus on issues of "development and prosperity."

Relations between the world's two most populous nations, who fought a war in 1962, have been strained, most recently after incidents along their border. Indian authorities in April accused Chinese troops of crossing several miles into Indian-held territory in the remote Himalayan region of Ladakh. China denied any incursion.

Mr. Modi is expected to adopt a more proactive foreign policy than the previous administration, focusing on buttressing India's economic prospects. One of his trickiest challenges will be dealing with an increasingly assertive and well-armed China, which is looking to play a larger role in South Asia.

China likely is hoping Mr. Modi's administration will be less assertive on strategic issues and more focused on economic collaboration. "Modi is unlikely to act as vehemently as [Japanese Prime Minister Shinzo Abe ], as it would be of no benefit to India's economy at all," said Liu Zongyi, an analyst from the Shanghai Institutes for International Studies, in a recent article in China's Global Times.

"As a right-winger in Indian politics, Modi is more likely to become India's Nixon who will further propel the China-India relationship," he said, referring to U.S. President Richard Nixon's breakthrough with China in the 1970s.

Some BJP politicians see the India-China relationship as a potential game changer for the Indian economy, as a means to unlock its manufacturing sector and revamp infrastructure. But others see the benefits of their partnership traveling mostly in one direction. Indians have long complained about the trade deficit with China, which has grown to more than $30 billion from $1 billion in 2002.

Brahma Chellaney, an Indian strategic-affairs analyst, said Mr. Modi would likely push to correct "the lopsided and asymmetrical relationship," but was unlikely to see China as a pivotal partner in his plans for an economic turnaround.

Instead, Mr. Modi would likely try to deepen ties with other democracies in Asia, particularly Japan. A recent survey of Japanese manufacturers showed, India was the second-favorite investment destination after Indonesia.

Mr. Modi and Mr. Abe are expected to pick up negotiations on defense cooperation and a civil nuclear accord that would allow companies like Hitachi to export nuclear reactors and technology to a power-starved India.

The Wall Street Journal