To reopen the border between Morocco and Algeria, which has been closed for 18 years, requires deeper examination, Moroccan Minister of Communication Mustapha El Khalfi said while visiting Algiers on Monday.

"The issue of reopening the border requires good preparation and necessary time," El Khalfi was quoted by local APS news agency as saying, adding that the issue is related to the "sovereignty of Algeria."

Algiers closed the border with Morocco in 1994, after Rabat started imposing visa entry on Algerian nationals following an attack in the Moroccan city of Marrakech.

In August, 1994, two Spanish tourists were killed when gunmen opened fire at the Atlas Asni hotel in Marrakech. While there are allegations that Islamic extremists related to the Algerian militant movement were behind the incident, some Moroccan officials also claim that members of the Algerian security services were behind the attack.

The issue of reopening the border has been evoked by the two North African nations, thanks to bilateral efforts to ease up tensions.

Algerian Prime Minister Ahmed Ouyahia recently said the land border with Morocco would be reopened "sooner or later."

"Things are excellently progressing thanks to exchanging visits and meetings between the two sides, which would lead to warming up the bilateral relations," Ouyahia said. "So, the border will necessarily be reopened."

El Khalfi arrived in Algiers on Sunday evening for a three-day visit.