Security protecting Indonesia's president has been tightened in the wake of an intelligence warning that terrorists are plotting to kidnap high-ranking officials, a spokesman said Sunday. "Therefore, for the time being the president cannot shake hands with the public," presidential spokesman Andi Mallarangeng told reporters minutes after President Susilo Bambang Yudhoyono arrived on Nias Island. There were no other details about the security measures being implemented, the Associated Press reported. Yudhoyono frequently shakes hands and hugs members of the public. On Tuesday, Syamsir Siregar, chief of National Intelligence Agency told reporters that terrorists are plotting to kidnap high-ranking officials, including foreigners.