KATHMANDU, Nepal — A peculiar vaccine drama is unfolding at the international airport in Nepal’s capital. It involves a member of Bahrain’s royal family who arrived with thousands of doses of coronavirus vaccines from China for an expedition to Mount Everest.

Before setting out, a team of Bahraini climbers led by Sheikh Mohamed Hamad Mohamed al-Khalifa had announced that they would be coming with 2,000 doses of Covid-19 vaccines, which Nepal’s government said would be of the AstraZeneca kind.

This move would fulfill a pledge that the climbers had made to local villagers during another expedition last September — a promise of generosity that led the villagers to name a local hill “Bahrain Peak.”

But when the climbers arrived in the capital, Kathmandu, on Monday, an inquiry by Nepal’s drug regulators found that the vaccines they were carrying were actually the one developed by Sinopharm, a Chinese state-owned vaccine maker.

The Nepali authorities now find themselves in a fix: whether to accept the vaccine doses or refuse.

The doses are being held in cold storage at the airport, and the climbers have been quarantined at a hotel as the authorities ponder how to handle the situation.

Nepal has largely relied on the AstraZeneca vaccine for its rollout, which is off to a slow start. Relying on a donation of one million doses from India, Nepal has vaccinated about 1.7 million people in a country of about 30 million.

Its efforts have been slowed because of a delay in the delivery of two million vaccine doses that it bought from the Serum Institute of India.

Although Nepal approved the emergency use of the Sinopharm vaccine after China pledged to give 500,000 doses to the country, it has not received the Chinese donation.

In September, the Bahraini climbers arrived in Nepal in a chartered plane to climb two mountains, Mount Manaslu and Lobuche Peak. The vaccine doses they were carrying this week were a gift for villagers in Samagaun, a gateway to Mount Manaslu.

The team of Bahraini climbers could not be reached for comment. But Mingma Sherpa, the owner of Seven Summit Treks, the agency that has been organizing the Bahrain team’s Everest expedition, said the complications might have resulted from miscommunication between Nepal’s foreign ministry and the health ministry.

He said the Sinopharm vaccine had also been used during Bahrain’s vaccination drive.

“It’s up to the government,” Mr. Sherpa said. “If they think it’s OK, the vaccines will be administered to villagers. If they think it’s risky to vaccinate the people, the team will take the vaccine back to Bahrain.”