FACTBOX: Developments in Zimbabwe

(Reuters) - Following are developments in Zimbabwe at 4:15 p.m. EDT on Tuesday:

* Denotes new or updated items:

* The U.N. Security Council will consider further steps on Zimbabwe if Harare ignores a council statement declaring a free and fair election run-off impossible, U.S. Ambassador Zalmay Khalilzad said.

* The international community will reject any attempt by President Robert Mugabe to declare himself president if he goes ahead with a planned run-off election, the U.S. State Department said.

The U.S. ambassador to Harare said the world could not stop the presidential run-off vote but southern Africa should declare Mugabe's government illegitimate.

The opposition Movement for Democratic Change (MDC) formally confirmed the decision to pull out of the election runoff in a letter delivered to the electoral commission.

Mugabe said no-one wanted to kill opposition leader Morgan Tsvangirai and he was under no threat.

Tsvangirai said he could be ready to leave the Dutch embassy in the coming days after receiving assurances for his safety.

Senegalese President Abdoulaye Wade said in a statement that Tsvangirai took refuge after being tipped off that soldiers were on the way to his house.

The U.N. Security Council has for the first time unanimously condemned violence against opposition supporters in Zimbabwe and said a free and fair presidential election is impossible now.

Both President Wade and South African ruling ANC leader Jacob Zuma said the presidential run-off must be postponed.

Mugabe's government said the withdrawal is too late to force the election to be cancelled and it will go ahead on June 27.

South Africa's COSATU trade union federation said it would mobilize the world's workers to isolate Mugabe, accusing him of ruling illegally.