DUBAI (Reuters) - Sayed Ahmed AlWadaei, a prominent Bahraini rights campaigner exiled in Britain, said on Saturday a Bahraini court had sentenced his wife to two months in jail in absentia this week and that his mother-in-law had begun a hunger strike in jail.

AlWadaei, director of the Bahrain Institute for Rights and Democracy (BIRD) and one of the most outspoken critics of the Gulf island kingdom, alleges the government’s treatment of his family was aimed at silencing his activism.

“Their escalation against both of my family members was no coincidence,” AlWadaei, who has lived in exile since 2012, told Reuters. Asked if Bahraini authorities were trying to muzzle him, he replied, “Of course. My wife was beaten, mistreated and threatened that they are going after our family to punish me. Now all their threats were executed.”

Bahraini authorities did not immediately respond to Reuters requests for comment.

A close U.S. and British ally, Sunni Muslim-ruled Bahrain has cracked down on the opposition, hailing mostly from the Shi’ite Muslim majority, since it crushed pro-democracy demonstrations they led in 2011.

Rights groups have accused authorities of seeking to stamp out dissent. The government says the opposition is linked to militants backed by their arch-enemy Iran who have carried out years of deadly bombing and shooting attacks on security forces.

AlWadaei’s wife Duaa was detained and interrogated as she and their son departed Bahrain’s airport after a visit in 2016.

When she complained that she was physically abused during questioning about his activities and movements - charges authorities have denied - she was charged with insulting state institutions and sentenced in absentia to two months in jail on Wednesday, AlWadaei said.

U.S. State Department spokeswoman Heather Nauert criticized Duaa AlWadaei’s sentence and urged the kingdom, where the U.S. bases its Fifth Fleet, not to prosecute free speech.

“We saw the report that a Bahraini criminal court sentenced her in absentia to ... two months in prison for allegedly insulting a state institution. Really?”

“We strongly urge the government to abide by its international obligations and commitments to respect human rights and fundamental freedoms, and that includes the freedom of expression.”

AlWadaei also said his mother-in-law Hajer Mansoor Hassan began a hunger strike on Tuesday to protest against alleged restrictions to her privacy and monitoring of phone calls, and was moved to an Interior Ministry hospital two days later.

She was sentenced to three years in jail in October for planting a “fake bomb” meant to taunt police. She denied the charges.

Bahrain’s National Institution for Human Rights (NIHR), a state body, said on Twitter that the Interior Ministry had described Mansoor’s health as “normal and stable.”

“(We have) not received any complaints or requests for help from Ms. Hajer Mansoor Ali or her representative to date,” the NIHR tweeted.

Another female activist at the same prison, Medina Ali, also began a hunger strike to protest against a strip search and in solidarity with Hassan, BIRD reported.