The Turkish president Recep Tayyip Erdoğan has called for the full lifting of the Saudi-led blockade of Qatar, as the week-old crisis deepened amid concerns about its humanitarian impact.

Erdogan’s comments came as the human rights group Amnesty International warned that the embargo – which includes harsh new restrictions on residence and travel – was splitting families up due to the requirement for Qatari citizens to leave neighbouring countries within 14 days.

According to one estimate there are more than 6,000 families in the Gulf where one spouse is Qatari and is facing forced repatriation. The Turkish intervention is in marked contrast to the role of the US president Donald Trump who on Friday threw his weight explicitly behind the actions of Saudi Arabia, Bahrain, Egypt and the United Arab Emirates, accusing Qatar of being “historically … a funder of terrorism at a very high level” – a claim denied by the small Gulf state.

Insisting that isolating Qatar would not resolve any regional problems, Erdoğan vowed that he would do everything in his power to help end the regional crisis.

“We will not abandon our Qatari brothers,” Erdoğan told members of his AKP party at a traditional Ramadan evening meal on Friday in Istanbul. “I say it should be lifted completely,” he said of the embargo.

Erdoğan’s comments came amid mounting evidence of the humanitarian impact of the blockade. Confirming claims by a Qatari human rights organisation on the impact on families, Amnesty said the blockade was already splitting families and “sowing fear”.

Qatar’s National Human Rights Committee has claimed that some 10,000 Gulf citizens had already been affected by the embargo.

“These steps result in tearing up families, disrupting businesses and interrupting students’ education across the region,” the NHRC said on Thursday in a news conference in Doha.

Amnesty’s James Lynch – recently returned from Doha – painted a similarly grim picture.

“These drastic measures are already having a brutal effect, splitting children from parents and husbands from wives,” said Lynch. “People from across the region – not only from Qatar, but also from the states implementing these measures – risk losing jobs and having their education disrupted.”

Documenting several cases, Amnesty described the case of one Qatari man, living in the UAE with his Emirati wife and family for more than a decade, who was refused entry and sent back to Qatar as he tried to return home to Dubai from Doha.

The man described his wife pleading to see her husband one last time as an officer refused, telling her to “go back”.

Amnesty’s claims echo similar accounts described to the Observer in recent days and also published in local media – often anonymously for fear of the impact on work and family.

The Turkish parliament has passed new legislation ratified by Erdoğan allowing the country to send military assistance to Qatar.

Turkey, along with Iran, has also been instrumental in helping Qatar keep open its air routes to the outside world following the closure of land borders and airspace by Qatar’s Arab Gulf neighbours, as well as stepping in to supply fresh dairy products to Qatar, the item hardest hit by the embargo.

The strong expressions of support for Doha from Turkey – which has long had regional foreign policies in line with Qatar, including support for revolutions during the Arab spring in 2011 and warmer relations with Iran than other Gulf states – has tempered some of the anxieties in Qatar, as the Emirates has appeared to strengthen its resolve in the midst of the standoff.

Qatar’s foreign minister, Sheikh Mohammed bin Abdulrahman al-Thani, travelled to Moscowon Saturday for talks on the crisis after visiting Germany on Friday.

Trump made his remarks on Friday despite a warning from the Pentagon that the blockade could hinder planned US operations in the region. Qatar hosts the Al Udeid air base, home to more than 11,000 US and coalition forces, many involved in the fight against Islamic State.