Nepal's parliament will select the nation's new prime minister on Sunday, choosing between the leaders of the top two political parties.

The new prime minister will have to deal with protests over the country's new constitution, as well as an unhappy neighbor India.

The 598 members of parliament will choose between Sushil Koirala of the Nepali Congress party and Khadga Prasad Oli of the Communist Party of Nepal-Unified Marxist Leninist.

Koirala became prime minister in 2014, but the constitution that was adopted last month required him to step down. He is, however, eligible to become prime minister again.

Ethnic Madhesis and other groups have been protesting in southern Nepal for weeks against the constitution. India, which has close ties to the Madhesis, is also unhappy with the new constitution.