Image copyright AP Image caption There was no meeting between Rex Tillerson and his Mexican counterpart Luis Videgaray

Mexican Foreign Secretary Luis Videgaray met senior White House aides without the State Department's knowledge, according to an official.

State Department acting spokesman Mark Toner said he was "unaware" the foreign minister was in Washington.

The secretary of state typically receives foreign diplomats during visits to the nation's capital.

The disconnect comes amid reports that the State Department has been sidelined in matters of foreign policy.

"We'll take that and get back to you. I was unaware that he was - the foreign minister was in town," Mr Toner said at a news conference on Thursday.

"I can't speak to whether there's going to be any meetings at the State Department at any level," he continued.

Mr Videgaray met President Donald Trump's son-in-law and senior adviser Jared Kushner, National Economic Council Directory Gary Cohn and National Security Adviser HR McMaster on Thursday.

Is Tillerson sidelined? Barbara Plett Usher, BBC state department correspondent

There's no question that Rex Tillerson is keeping an extraordinarily low profile for a secretary of state. The question is whether that's because the former CEO is still getting up to speed with a government role, or whether the State Department is being sidelined by members of the president's inner circle who also weigh in on foreign policy.

The Mexican foreign minister's schedule suggests the latter. The other part of the equation is the lack of senior staffing to drive the State Department policy agenda in a sharp elbowed town. To some extent that's a broader issue - a number of government agencies are still battling to get the White House to approve their nominations.

But there was a particularly thorough purge of Obama appointees at the State Department who could have smoothed the transition. And there is the prospect of steep budget cuts. All of which prompted four Senate Democrats to warn Mr Tillerson that the department is in danger of being carved out of foreign policy decisions.

The secretary of state has got his priorities right by making Asia one of his first trips. He heads there next week for talks with allies about North Korea. But again, the question is what he can achieve. "Diplomacy is a team sport," says Chris Hill, the chief US negotiator with North Korea from 2005-2009. "And I don't see the team there."

The Mexican diplomat later said he had spoken by phone to Secretary of State Rex Tillerson on Wednesday night to notify him of his arrival, and the two agreed to meet in person in a couple of weeks.

Mr Videgaray also said that Thursday's meeting was focused on raising concerns with the Trump administration about its consideration of separating migrant children from their parents at the border to discourage crossing into the US illegally.

"Family integrity is a basic human right," he said at the Mexican Embassy in Washington.

Media playback is unsupported on your device Media caption US immigration raids leave many 'afraid to open the door'

Earlier this week, a group of Democratic senators raised concern that the State Department was facing several challenges that could undermine US diplomatic leadership, according to BBC State Department Correspondent Barbara Plett Usher.

In a letter sent to Mr Tillerson, they said they were concerned the department was experiencing significant management challenges, was being left out of important foreign policy decisions and that Mr Trump's budget cuts could devastate American diplomacy.

Image copyright Reuters Image caption Mexico's foreign minister (R) expressed his irritation with US immigration policies to US Secretary of State Rex Tillerson (L) during their meeting last month

Mr Tillerson and Homeland Security Secretary John Kelly met Mr Videgaray two weeks ago in Mexico City as part of an effort to repair frayed relations between the two countries.

Relations between the neighbours are at their lowest point for decades.

Mexican officials have been rankled by President Trump's harsh rhetoric on immigration as well as his plan to build a multi-billion-dollar wall along the southern US border.

The president has also insisted that Mexico would pay for the wall - a claim that Mr Videgaray and other officials have flatly rejected.