KABUL (Reuters) - Afghan President Hamid Karzais election rival Abdullah Abdullah will announce on Sunday whether he will take part in next weeks disputed run-off vote, his campaign said after speculation mounted he will pull out. Abdullah cancelled a planned trip to India on Saturday, just before a deadline he had given Karzai to sack Afghanistans top election official was to expire. Afghanistan has been racked by weeks of political uncertainty after widespread fraud marred the first round, with security another major concern after a resurgent Taliban vowed to disrupt the November 7 run-off vote. With Afghanistans political future hanging in the balance, US President Barack Obama is also weighing whether to send thousands more troops to Afghanistan. Obama met US military leaders in Washington on Friday as part of a strategy review. Abdullahs campaign team issued a short statement on Saturday saying the former foreign minister had called a loya jirga (grand assembly of elders) for 9:30am on Sunday (5:00am British time). Dr Abdullah Abdullah will a give speech about the election and he will announce his decision in the loya jirga tent, the statement said. Abdullahs aides earlier said he had cancelled the trip to India because of uncertainty over the election. Western officials have noted that Abdullah has not opened any campaign offices in Afghanistan since the run-off was called last week. Neither candidate has campaigned openly. The signs are there. (Abdullahs) not doing any campaigning. Everyone is looking at the two camps and willing them to do some form of accommodation that will avoid a run-off, one Western diplomat, who asked not to be identified, told Reuters. Diplomats and analysts have said that, according to the constitution, it was possible the run-off might go ahead with Karzai as the only candidate if Abdullah pulls out. They fear that would have a serious impact on the governments legitimacy. If Abdullah boycotts, voter turnout will be very low and Karzai will be declared winner but with a very low legitimacy, said Haroun Mir, a Kabul-based analyst and director of Afghanistans Centre for Research and Policy Studies. Talk of a possible power-sharing deal between Karzai and Abdullah has also grown as a possible solution to the deadlock. The US embassy in Kabul said it was a matter for Karzai and Abdullah to decide if they could come up with a constitutionally sound solution that was acceptable to Afghans.