ISLAMABAD -- Pakistan's beleaguered president, Asif Ali Zardari, is under increasing pressure to step down or to relinquish most of his sweeping powers immediately, as growing political tension threatens the stability of the Muslim nation in the midst of a critical battle with Taliban militants.

In an attempt to defuse the situation, Mr. Zardari over the weekend transferred command of the country's nuclear arsenal to Prime Minister Yousaf Raza Gilani, signaling his willingness to shed some of his powers. Mr. Gilani said Sunday the transfer of the chairmanship was "a true litmus test" of relations between him and the president.

Mr. Zardari's move could be the first in a series to diminish his power in an effort to retain his party's backing. He is under pressure also to shed his powers to dismiss the parliament and to make key military appointments.

But analysts said the president's weekend maneuver had only symbolic value. It seems to have failed to appease his opponents, who said the president needed to act sooner.

"It does not have any political value for Mr. Zardari in the power struggle," said Maleeha Lodhi, a former Pakistani ambassador and a senior fellow at the Woodrow Wilson International Center for Scholars in Washington.