Supporters of President Hassan Rouhani of Iran have won more seats in parliamentary runoff elections, the Iranian state news media reported Saturday, but they failed to win enough of the 68 contested seats to secure a majority, limiting their ability to carry out significant political and social changes.

The gains made by the moderates and reformists were not enough to decisively alter the balance of power in Iran, the president’s supporters acknowledged. They added that political clashes between their lawmakers and conservative hard-liners were bound to increase.

“Expect a Parliament with a slightly friendlier tone, but also many political crises,” said Farshad Ghorbanpour, a political analyst close to the government.

After Friday’s runoff elections for races that were not decided in the first round of voting in February, the reformists and moderate supporters of Mr. Rouhani hold 122 seats in the 290-member Parliament, and the conservative hard-liners have 84, the state media reported.