Jerusalem (AFP) - British foreign minister Boris Johnson has warned that the alternative to a two-state solution in the Israeli-Palestinian conflict is an "apartheid system," in an interview with an Israeli newspaper published Thursday.

Johnson had a whistlestop 24-hour visit to Israel and the Palestinian territories Wednesday in which he reaffirmed British support for Israel but criticised settlement building in the occupied West Bank.

"What we are saying is that you have to have a two-state solution or else you have a kind of apartheid system," Johnson said in an interview published in the English-language daily The Jerusalem Post Thursday.

The two-state solution, meaning the creation of a Palestinian state existing in peace alongside Israel, is a key policy goal of the international community.

US President Donald Trump cast uncertainty over his country's commitment to the idea when he met Israeli Prime Minister Benjamin Netanyahu at the White House in February, saying he would be open to a single state if it led to peace.

Palestinians fear the prospect of a single state in which Israel would not give the same rights to Jews and Arabs, with senior leaders warning it would constitute "apartheid."

In Ramallah on Wednesday, Johnson stressed that his government's policy was "absolutely unchanged" and they remain committed to two states.

The international community considers continuing settlement growth in the West Bank a major obstacle to peace.

Parts of Netanyahu's government, considered the most right-wing in Israel's history, advocate annexing at least part of the occupied West Bank.

When meeting Netanyahu on Wednesday, Johnson stressed Britain's "rock-like" support of Israel, but also touched on settlement building.

"Israel has first and foremost an absolute right to live in security, and the people of Israel deserve to be safe from terrorism," Johnson said.

But he later added: "Of course we must also try to remove obstacles to peace and progress such as the settlements."