Russian President Vladimir Putin on Wednesday pardoned an Israeli-US woman jailed for drug trafficking, on the eve of a visit to Moscow by Israel's Prime Minister Benjamin Netanyahu.

Netanyahu, who has pushed hard for her release in his campaign for re-election March 2, is to brief Putin on President Donald Trump's Middle East plan.

"I thank my friend President Putin for having pardoned Naama Issahar," Netanyahu said in a statement before leaving Washington.

"I am looking forward to our meeting tomorrow (Thursday) in which we will discuss the (Trump) plan and latest events in the region," he added.

Naama Issachar, 26, was arrested at Moscow's Sheremetyevo airport in April 2019 as she travelled from India to Israel and was sentenced in October to seven and a half years in prison.

Russian authorities said they found nine grammes (three ounces) of cannabis in her checked luggage.

"Guided by the principles of humanity, I pardon Naama Issachar," Putin said in the decree cited by the Kremlin.

The young woman's fate had sparked a wave of sympathy in Israel where Netanyahu had pledged to do everything for her release.

The Israeli newspaper Yediot Aharonot reported that the young woman would return to Israel on Thursday in Netanyahu's plane.

"I am moved of course. I'm thinking about Naama. I don't know if she knows, if they told her," Naama's mother Yaffa Issachar said, thanking Netanyahu, the Israeli people and others who worked for her release.

In December, Issachar lost an appeal against her sentence which Netanyahu has described as disproportionate.

When travelling to Israel last week for commemorations for the liberation of the Nazi death camp at Auschwitz 75 years ago, Putin appeared before the cameras with Issachar's mother and Netanyahu.

Naama Issachar, 26, was arrested at Moscow's Sheremetyevo airport in April 2019
Naama Issachar, 26, was arrested at Moscow's Sheremetyevo airport in April 2019 AFP / Kirill KUDRYAVTSEV

Putin said he had assured her mother that all would go well while Yaffa Issachar said the Russian leader had promised to send her daughter home.

Issachar's Russian lawyer Vadim Kliouvgant told AFP "the procedure for her release was underway, in line with the decree."

Naama Issachar, imprisoned in the Moscow region, had on Sunday signed a request for a pardon addressed to Putin. She had initially refused to do so.

Israeli media reported that there were negotiations to exchange Issachar for a Russian imprisoned in Israel.

When she was sentenced in October, Russian and Israeli media had raised the possibility that Issachar be traded for Alexei Bourkov, a Russian citizen detained in Israel since 2015 and accused of computer hacking by the United States, who asked for his extradition.

However, he was extradited to the United States in November.

Issachar's sentence was upheld on appeal in December.

During an appeal hearing, Issachar had proclaimed her innocence, denouncing the absurdity of accusations against her.

The Israeli foreign ministry had called the verdict "harsh and disproportionate" and President Reuven Rivlin had appealed to Putin's "mercy and compassion" when asking him to intervene in the case.

It remains to be seen how much Issachar's release and Netanyahu's visit to Washington boost his re-election chances.

Analysts said the details of Trump's plan could offer political benefits to Netanyahu, delighting rightwing voters with calls for the annexation of West Bank settlements and possibly appeasing some on the left with nominal support for a Palestinian state.

Russia said it would study Trump's plan and called on Israelis and Palestinians to negotiate directly to find a "mutually acceptable compromise."