Gambia is coming under more pressure to halt all executions, as fears rise the government could kill dozens of prisoners in coming weeks.

Rights group Amnesty International says Gambian President Yahya Jammeh must retract a threat to execute all death row inmates in his country, and place an immediate moratorium on further executions.

Late Tuesday, the U.S. State Department also called for an immediate halt and said it is “greatly concerned” by Gambia's execution of nine prisoners, announced Monday.

Gambia said the nine death row inmates, including one woman and two Senegalese nationals, had been executed by firing squad. There are conflicting reports about when the executions took place.

Senegalese Prime Minister Abdoul Mbaye summoned the Gambian ambassador Wednesday, and according to a statement, expressed “strong disapproval” of the secrecy around the executions.

He said the rights of other Senegalese detained in Gambia must be “scrupulously respected.”

Rights groups plan to hold a protest outside the Gambian High Commission in Senegal's capital, Dakar, on Thursday.

Gambian President Jammeh said recently that all death sentences in the country will be carried out by mid-September. Another 39 prisoners are believed to be on Gambia's death row.

The U.S. is calling for a review of all of Gambia's capital punishment cases to ensure they are in accordance with Gambia's domestic laws and international human rights treaties.

The United Nations, African Union, European Union, and former colonial power Britain have also called on President Jammeh to reconsider or renounce his plans.