Turkish security forces have detained some 1,104 irregular migrants across its largest metropolitan city Istanbul, sources said Sunday.

Security units, in coordination with the Anti-Migrant Smuggling Branch, held the irregular migrants from various public areas in various districts of Istanbul, said a source who did not want to be named due to media restrictions.

They were later referred to local migration offices for due process. Irregular migrants are first held in repatriation camps for a short period before being returned to their home countries.

Sunday's operations come among heightened measures against irregular migration in the country.

Elsewhere, 74 irregular migrants were sent to eastern Erzurum from Istanbul via Kars for deportation Sunday.

The processing of the irregular migrants, detained from Istanbul's various districts and sent to Kars for deportation, was completed by the local police before being sent to Erzurum's Aşkale Deportation Center.

Earlier Saturday, another 1,682 irregular migrants were held across Turkey's most populated city.

In the meanwhile, at least 221 Afghan nationals who entered Turkey illegally were flown back to Afghanistan on Friday.

According to the local migration office, the plane carrying the migrants to Afghanistan took off from Istanbul Airport, as part of the government's efforts to combat irregular migration.

In May, the Interior Ministry said that Turkey has so far deported more than 28,500 irregular migrants this year alone.

Turkey has been a key transit point for asylum seekers aiming to cross to Europe to start new lives, especially those fleeing war and persecution.

The country already hosts over 4 million refugees, more than any other country in the world, and is taking new security measures on its borders to humanely prevent a fresh influx of migrants.