The aircraft was flying to the Loisaba Conservancy, a wildlife reserve and safari destination in northern Kenya, when it crashed, according to a preliminary report from Archers Post police station seen by Reuters.

All seven people - six passengers and one pilot - were killed, authorities said.

A State Department spokesperson said five Americans were among the dead, while Ecuador's presidential office confirmed intelligence head Michele Sensi-Contugi and his wife Stephany Hollihan - who held U.S. citizenship - were also killed.

"The U.S. Embassy is in touch with local authorities and is providing consular assistance," the State Department said.

The preliminary police report listed Sensi-Contugi and his wife as tourists.

Luxury tour agency &Beyond, which offered the excursion the tourists were on, said in a statement that the cause of the crash was yet to be determined.

The Kenya Red Cross said that search and recovery efforts were being hampered by difficult terrain and a fire at the crash site.

(Reporting by Humphrey Malalo, Vincent Mumo Nzilani and Ammu Kannampilly in Nairobi, Elias Biryabarema in Kampala and Nilutpal Timsina in Johannesburg; Additional reporting by Alexandra Valencia in Quito; Writing by Kylie Madry; Editing by Alexander Winning, Alex Richardson and Alistair Bell)