Mexico’s central bank said it has filed a suit with the Supreme Court over a law backed by President Andres Manuel Lopez Obrador that caps public sector salaries, in the latest challenge to the new leftist leader’s populist agenda.

The Bank of Mexico said in a statement late on Thursday had filed the suit in order for the court to rule on whether the new law compromised its constitutionally-guaranteed independence.

Lopez Obrador took office in December and is pushing through a raft of cost-cutting measures to fund increased social spending and infrastructure projects.

Recent moves by his government and leftist majority in Congress have rattled financial markets, but Lopez Obrador has repeatedly stressed that he will respect the central bank’s autonomy.

Citing risks to inflation from new policies, policymakers at the bank hiked interest rates in November and December, taking rates to an over 10-year high and saddling the new government with higher borrowing costs.

The central bank said in its statement that some of its employees had filed their own injunctions against the new law and that it would follow court rulings on those suits.

Lopez Obrador cut his own salary to 40 percent of what his predecessor earned, to around $5,500 per month, well-below salaries that high-level bureaucrats were being paid. The law would cap public sector salaries at the same level he is getting.

Earlier this week, the country’s anti-trust agency also filed suit over the law, claiming its investigators qualified as technical experts who are an exception under the new rules.

In early December, the Supreme Court issued a suspension of the law until it had made a definitive ruling after opposition lawmakers filed a challenge.

Lopez Obrador is set to name two new members to the central bank’s five-member board soon, and he will be able to replace all but one deputy governor during his six-year term.

He has said he will nominate left-leaning economist Gerardo Esquivel, who was first tapped as Lopez Obrador’s deputy finance minister, and independent economist Jonathan Heath to the board but he has yet to formally name them for Senate approval.

($1 = 19.6209 Mexican pesos)