Prime Minister Narendra Modi’s ruling party will likely need help from junior partners to form a government under the rules of India’s parliamentary system, early election results indicated on Tuesday.

In a 2019 election that handed Mr. Modi a second consecutive term, his Bharatiya Janata Party won 303 of the 543 seats in Parliament. That was well over the 272 seats it needed to rule on its own.

This time, exit polls released over the weekend suggested that the B.J.P. would once again easily win more than 272 seats. But as of early Tuesday afternoon, official voting results indicated that it would win about 240 seats instead.

Winning that much support — 44 percent of the seats in Parliament’s lower house — is an impressive feat in India or any other country. And the new math should not prevent Mr. Modi from securing a third consecutive term as prime minister.

But the dip in the B.J.P.’s electoral support, far short of Mr. Modi’s goal and his last electoral performance, will likely have political ramifications.

At a minimum, the B.J.P. will have to depend more on the junior members of its existing multiparty alliance. Two of the most prominent parties do not share Mr. Modi’s Hindu-first agenda.

And if the governing alliance does not win a majority, the B.J.P. will be able to form a government only by adding new partners.

It may not come to that. As of Tuesday afternoon the alliance was on track to scrape by with a narrow parliamentary majority — far short of its target of 400 seats, but enough to stay in power with its existing members.