Mexico has boasted of a sharp drop in the number of migrants attempting to travel through the country ahead of a US deadline for its southern neighbour to show that it is cracking down on irregular migration.

The foreign minister, Marcelo Ebrard, told reporters on Monday the migrant flow through Mexico had diminished by 36.2% since 7 June – when the Mexican government agreed to increase immigration enforcement to avoid Donald Trump imposing escalating trade tariffs.

Figures from the National Immigration Institute showed an average of 4,156 migrants entered Mexico daily through its southern border during the week of 1-7 June. That figure fell to roughly 2,652 people a day during the week ending 19 July.

Ebrard attributed that decline to the deployment of 20,000 members of a newly formed militarised police force and “immigration laws being enforced”.

He added: “We have not agreed on a number for the next 45 days” – with the Trump administration – “but we’re going to keep up this effort so the trend continues downward.”

President Andrés Manuel López Obrador once promised to not “do the dirty work” of any foreign government on the immigration issue, but his administration has taken action amid fears that Trump’s fury over the steady stream of migrants could dent Mexico’s export-driven economy.

The US president, however, has recently complimented Mexico as the country detains and deports ever larger numbers of migrants – and fewer migrants make it to the US border.

Migrant apprehensions on the US southern border fell in June to some 100,000 people, according to US data. Observers say the figures usually drop during the scorching summer months.

Mexico’s deal with Trump included a provision to revise the progress Mexico was making after 45 days. The two sides would also discuss designating Mexico as a “safe third country” for asylum seekers if it was deemed Mexico’s efforts to stop migrants were inadequate.

Such a deal would oblige asylum seekers, who currently make up a large part of those apprehended at the US border, to seek refuge in Mexico instead.

Ebrard said on Monday that Mexico would not discuss the safe third country issue further and he did not know the Trump administration’s stance on the issue.

He added the previous deal was not addressed during a weekend meeting with the US secretary of state, Mike Pompeo.

“I can’t anticipate what their stance is [on the safe third country issue] but the Mexican position is very clear. We are not going to change our position. We don’t agree, and we have not accepted a negotiation about it,” Ebrard said.