Washington ? The United States built pressure on Afghan President Hamid Karzai on Wednesday, signaling that a troop increase could hinge on a successful runoff election and that the Obama administration would be receptive to a power-sharing deal between Karzai and his chief rival.

A coalition government or other political arrangement that included Karzai’s rival, former Foreign Minister Abdullah Abdullah, could provide a critical internal check on Karzai, who is widely favored to win the presidential runoff set for Nov. 7.

President Barack Obama and Sen. John Kerry, who pressed the administration’s interests in weekend talks with Karzai in Kabul, both hinted Wednesday that pending deliberations on possible U.S. troop increases in Afghanistan could be affected by the Afghan leader’s behavior.

Karzai’s weak and corruption-riddled government has been blamed in part for the resurgence of the Taliban and for widespread Afghan civilian disillusionment. The Afghan national election in August was marred by massive fraud that led to the discarding of a third of the results, providing a wedge for the U.S. to press Karzai to agree to the runoff with Abdullah.

Kerry, whose meetings with Karzai helped lead to the runoff agreement over the weekend, said Wednesday after a White House session with Obama that the president should wait until after the new election to make his decision on troop strength.

Obama himself said Wednesday in a television interview he might not announce his decision on sending more troops until after the runoff.

Both statements had the subtle force of increasing pressure on Karzai by implying that the administration’s decision on U.S. troop strength in Afghanistan might depend on how the runoff turns out.

The Massachusetts Democrat said Wednesday that it wasn’t “common sense” for Obama to determine whether more U.S. troops should go to Afghanistan without knowing the election results. “You really want to know that this has worked, and you want to know what’s coming out of it,” Kerry said.

Officials said Obama’s pending decision had prominently figured in the U.S. discussions with Karzai about how to resolve the political impasse.

Several officials stressed that the looming troop plan decision was not used overtly to force Karzai to concede on the election’s contested first round, but one highly placed U.S. official in Afghanistan said the United States used Obama’s deliberation over troop numbers as leverage.

That official spoke on condition of anonymity because Obama has not announced whether he will agree to a U.S. military request for thousands of additional forces.