The U.S. envoy to Israel has urged Prime Minister Benjamin Netanyahu to slow progress on a contentious judicial overhaul.
He added that the issue could make it harder for Washington to help him promote ties with Saudi Arabia or deal with Iran.
For weeks, Israel has been in an uproar over Netanyahu's hard-right government's plan to carry through changes to the judiciary, which critics say endangers the country's democratic checks and balances.
Israel's parliament may on Monday hold the first of three votes on a bill that would increase the government's sway in selecting judges while setting limits to the Supreme Court's power to strike down laws or rule against the executive.
"We're telling the Prime Minister, as I tell my kids, pump the brakes, slow down, try to get a consensus, bring the parties together," Ambassador Tom Nides told CNN podcast The Axe Files, published late Saturday.
While Nides emphasized that Israel had the United States' support on security and at the United Nations, he also said that Netanyahu's stated hope of forging diplomatic ties with Saudi Arabia or dealing with Iran's nuclear program, was at stake.
"The Prime Minister wants to do big things, okay? He tells us he wants to do big things," Nides said. "I said to him, to the prime minister, a hundred times, we can't spend time with things we want to work on together if your backyard's on fire."
Netanyahu spoke about the friction in Israel at a weekly cabinet meeting, though he did not reference Nides' comments specifically.
"I'm happy to disappoint our enemies and also reassure our friends – Israel was and will remain a strong and vibrant democracy. An independent democracy," he said.
Diaspora Affairs Minister Amichai Chikli had a more contentious take on Nides, telling public broadcaster Kan: "I tell the American ambassador, you pump the brakes. Mind your own business. You are not sovereign here to discuss judicial reforms. We're happy to discuss diplomatic and security matters with you but respect our democracy."
Warning Israel is on the brink of a "constitutional and social collapse," President Isaac Herzog is trying to bring the government and the opposition together to agree on legal reforms and freeze legislation on the present plan, which successive polls have shown has relatively little support and which has triggered nationwide protests.
Earlier Saturday, more than 100,000 Israels took to the streets in a show of opposition to the planned judicial reforms.
It was the seventh consecutive week that people have protested against the government's controversial legal plans to deliberately weaken the Supreme Court.
The aim of the reforms is to give parliament the power to overturn Supreme Court decisions with a simple majority. Politicians are also to be given more influence in the appointment of judges.
Netanyahu, who is on trial for corruption that he denies, has said the changes are needed in order to restore the balance between the government, the Knesset and the judiciary, which some in his coalition accuse of elitism and overreaching its powers to interfere in the political sphere.
Critics see this as a threat to the democratic separation of powers. They also fear that the reforms could allow Prime Minister Netanyahu to escape conviction in his corruption trial.
In the absence of a written constitution in Israel, the Supreme Court has a special role to play in upholding the rule of law and human rights. However, the extreme-right religious government argues that the court currently exerts too much political influence.
In Tel Aviv, demonstrators gathered in the city center, with many waving Israeli flags and carrying signs that read, "Israel must not become a dictatorship" or called for support from the international community, saying "Biden, Macron – help us."
Officials closed several streets earlier in the day due to the rally.
Protests were also held in Jerusalem, Haifa and Beersheva.
